The IMMC thanks all those that attended our two August 30, 2005 Public Workshops. We appreciated the opportunity to meet with you, formally introduce our project, and learn of your interests and concerns about the project. The questions and concerns expressed at the Public Workshops are summarized in this document by session and are organized by the workshop "table topics" including: Mineral Resource Zone, Geology, Dewatering, Metallurgical Processes, Ceramics, Tree Survey, Socioeconomics, Traffic, and Noise. Some of the questions and concerns identified by workshop participants may seem similar or repetitive, however, for the sake of completeness, responses have been provided below for each.
The Idaho-Maryland Mining Corporation (IMMC) has a commitment to inform the community of its proposal to reopen the historical Idaho-Maryland Mine. As such, within a month of the project permit applications being accepted as complete by the City of Grass Valley in May 2005, the IMMC began to implement a community relations outreach program. As part of that program, information booths have been staged at numerous community events to elicit community interests and concerns. In August 2005, two public workshops were conducted. Hosting each of the table venues were the technical experts that developed the environmental analyses or industrial process descriptions contained in the Idaho-Maryland Mine Project Applications for a Mineral Exploration and Mine Use Permit. A summary of their individual presentations and the application documents may be found on the website by accessing the Public Documents tab.
Our community relations outreach program will complement the program that the City of Grass Valley will initiate in late 2005 when it undertakes the studies required by the California Environmental Quality Act (CEQA) and the Surface Mining and Reclamation Act (SMARA). We look forward to hosting workshops in the future that focus on the matters raised at the August meetings. In addition, we will continue to have information booths at upcoming community events so that we may be accessible to you. Please periodically check our calendar for our upcoming venues.
Announcements of future meetings will be posted to our website, published in The Union, or developed as postcard or email invitations to those that have elected to be part of our mailing list. If you would like us to meet with you individually, make a presentation to your organization, or if you would like to be part of our mailing list, please notify us at 530-271-0679 or .
a) What is the separation of surface and mineral rights?
In the Grass Valley area, after the U.S. Government received the lands from Mexico, an individual may have been granted (from the U.S. Government) surface rights along with mineral rights to the center of the earth, or surface rights down to a certain distance below the surface (such as 50 feet, 200 feet, or other depth), or just a portion of the mineral rights below the surface. The owner then has the right to use or sell what he owns. Likewise, airspace may be sold above the surface, as with a condominium.
b) What is the process for mineral land classification?
Please refer to the answer to d) below.
c) What effect does an MRZ classification have on your property?
The classification is a State zoning that informs local government agencies and the public where a significant mineral resource exists. It can also be used in local government zoning when developing general plans. If your property is classified MRZ-2a or 2b, any land-use decision that is made by the lead agency (For the Idaho-Maryland Project, the City of Grass Valley is the lead agency) must take into consideration the underlying mineral resource. Article 4, section 2762 of SMARA specifies that within 12 months after the State Mining and Geology Board submits the mineral land classification to the lead agency, the lead agency shall establish mineral resource management policies to be incorporated in its general plan which will (1) Recognize mineral information classified by the State Geologist, (2) Assist in the management of land-use which affect areas of statewide and regional significance, and (3) Emphasize the conservation and development of identified mineral deposits.
d) How do we classify lands as mineral resources?
In California, classification of land includes analysis of geologic and mining-related literature, compilation of geologic maps, plotting of reported mines and prospects, site investigations, selected sampling of rocks for analysis of their gold and silver content, geologic field mapping and analysis of aerial photographs.
This information is then integrated and evaluated in order to serve as the basis for assigning mineral resource zones to areas in accordance with the mineral land classification guidelines adopted by the State Mining and Geology Board.
e) When was the classification of the project area done?
The Mineral Land Classification study of Nevada County was conducted over a three-year period from October 1987 to October 1990.
f) What is the purpose of the classification?
The purpose of classification is to provide land-use regulators, local property owners, and the mining industry with scientific information regarding the nature, occurrence, and distribution of mineral deposits. The information is intended for collective use by these groups in land-use planning, mineral conservation, and mineral development. The primary objective of mineral land classification is to ensure that the mineral potential of land is recognized and considered before land-use decisions which could preclude mining are made.
a) If you own the land do you own the mineral rights?
Owners of the land (surface rights) do not also automatically own the mineral rights. In the Grass Valley area, after the U.S. Government received the lands from Mexico, an individual may have been granted (from the U.S. Government) surface rights along with mineral rights to the center of the earth, or surface rights down to a certain distance below the surface (such as 50 feet, 200 feet, or other depth), or just a portion of the mineral rights below the surface. The owner then has the right to use or sell what he owns. Likewise, airspace may be sold above the surface, as with a condominium.
b) What are the definitions of the MRZ-2b, MRZ-2a, and MRZ-3 mineral resource zone classifications?
MRZ-2a areas contain significant measured mineral resources. Areas classified MRZ-2a contain discovered mineral deposits that represent either measured or indicated reserves as determined by such evidence as drilling records, sampling analysis, surface exposures, and mine information. This category contains known economic mineral deposits as defined by the State of California.
The MRZ-2a areas are usually restricted to areas of existing mining operations.
MRZ-2b areas identify land containing significant inferred mineral resources. These areas contain either inferred reserves or deposits that are presently sub-economic as determined by limited sample analysis, exposure, and past mining history. Further exploration work and/or changes in technology or economics could result in upgrading areas classified MRZ-2b to MRZ-2a.
MRZ-3a areas are underlain by geologic settings within which undiscovered mineral resources similar to known deposits in the same producing district or region may be reasonably expected to exist.
c) How are the land classifications done for zoning MRZ3?
All classification of land is conducted in the same manner (refer to b) above)
d) Why was the Idaho Maryland site classified MRZ-2b instead of MRZ-2a?
When the classification was done between 1987-1990, the State of California Division of Mines and Geology (now the California Geological Survey, or CGS) used whatever information was available at the time such as geologic maps, underground mine maps, claim maps, and historical mine information. Also, the State conducted geologic site investigations and plotted historical surface mine workings. Since the classification of the Idaho-Maryland Mine area, Idaho-Maryland Mining Corp. has conducted additional exploration of the area (including drilling), economic assessments, and evaluations in such areas as mine dewatering and tailings uses. If CGS were to conduct another classification study, an analysis of this new information could possibly upgrade the classification of this area to an MRZ-2a.
Yes. As a public company reporting in both the United States and Canada, Emgold Mining Corporation must disclose mineral resources and reserves in accordance with securities regulations in both jurisdictions. The regulations in the United States are SEC Industry Guide 7 and in Canada, National Instrument 43-101. A Preliminary Assessment Technical Report was prepared by AMEC Americas Ltd. in November 2004. The report is an independent qualified person's review and evaluation of the Idaho-Maryland project in the form of a Technical Report as defined in National Instrument 43-101 ("Idaho-Maryland Mine Technical Report and Preliminary Assessment, November 22, 2004"). The Technical Report updates Emgold's previous gold resource base. Using the historic Idaho-Maryland Mine Call Factor ("MCF") of 1.44, the new gold resource consists of Measured and Indicated Mineral Resources of 1.67 million tons at 0.28 opt containing 472,000 ounces of gold and Inferred Minerals Resources of 2.53 million tons at 0.38 opt containing an additional 952,000 ounces of gold.
b) Will the mine have arsenic problems?
Arsenic is not anticipated because the mine did not have a history of having arsenic in the ore. However, additional testing to confirm our understanding may be conducted during the EIR process.
c) What is the cut-off grade for ore at the Idaho-Maryland, 0.2 oz/ton?
The cut-off grade of the existing gold resources is 0.1 ounce per ton.
d) How much gold is left at the Idaho-Maryland Mine?
See a) above. The potential to add gold ounces to our resource blocks is very good. Company geologists are confident that the current resource blocks can be expanded by underground drilling, and that known gold-bearing veins can be extended. Historically the bottoms of the veins of the Grass Valley District have never been reached, and so we have every reason to believe that these ore bearing veins will continue at depth.
e) Have you done any mineral exploration?
We have conducted mineral exploration to the extent possible from the surface. Once underground we will be able to do a much more thorough job of mineral exploration.
f) Logistics of exploration being conducted during the development of the decline and waste rock storage were raised as concerns.
Mine development rock will be temporarily stockpiled on the surface until the ceramics plant is built and begins processing it.
g) Are you mining serpentine?
We may encounter serpentine in some areas underground, however, it will be a small percentage of the total rock mined.
a) Concern was expressed over effects of blasting, e.g., vibration.
Initially, blasting will be conducted during the daytime and early evening hours only. As the decline advancement progresses deeper it will become further from people on the surface. During decline development, blasting vibrations will be monitored from the surface using a seismograph and feeling for ground vibrations. Once the decline has progressed to a depth such that the effects of blasting can no longer be felt from the surface we can begin blasting activities anytime during the day or night.
Blasting vibrations can also be reduced by the use of proper blasting techniques. Modern blasting techniques utilize multiple small blasts separated by short delays instead of a single, large blast. This limits the amount of explosive charge used and reduces the amount of blasting vibrations generated during blasting. This is the most effective means we have at limiting blasting vibrations.
b) Where is the location of underground workings?
The Idaho-Maryland property consists of 2,750 acres of mineral lands which includes the historic underground workings. The property is located 1.5 miles east of the center of the City of Grass Valley and lies primarily between Idaho-Maryland Road, Brunswick Road, East Bennett Road, and State Route 174.
Historic underground workings are situated beneath and roughly parallel to Whispering Pines Lane and Brunswick Road. Shafts were used to access underground workings. The New Brunswick shaft, located near the intersection of East Bennett Road and Brunswick Road, remains accessible and is located adjacent to the large concrete structure, which was the ore and waste bin for the mine.
c) How many gold ounces/per year will be produced?
The Idaho-Maryland Mine, discovered in 1851, produced gold from 1862 through 1956 and is considered the second largest historical underground gold producer in California. Total recorded production was 2,383,000 ounces of gold from 5,546,000 short tons for a recovered grade of 0.43 ounces of gold per short ton ("opt"). The maximum historical gold produced from the Idaho-Maryland gold mills was approximately 138,000 ounces of gold per year.
As a public company reporting in both the United States and Canada, Emgold Mining Corporation must disclose mineral resources and reserves in accordance with securities regulations in both jurisdictions. The regulations in the United States are SEC Industry Guide 7 and in Canada, National Instrument 43-101. A Preliminary Assessment Technical Report was prepared by AMEC Americas Ltd. in November 2004. The report is an independent qualified person's review and evaluation of the Idaho-Maryland project in the form of a Technical Report as defined in National Instrument 43-101 ("Idaho-Maryland Mine Technical Report and Preliminary Assessment, November 22, 2004"). The Technical Report updates Emgold's previous gold resource base. Using the historic Idaho-Maryland Mine Call Factor ("MCF") of 1.44, the new gold resource consists of Measured and Indicated Mineral Resources of 1.67 million tons at 0.28 opt containing 472,000 ounces of gold and Inferred Minerals Resources of 2.53 million tons at 0.38 opt containing an additional 952,000 ounces of gold. Under US and Canadian Securities rules, Emgold cannot disclose projected gold production until confirmatory exploration is completed and the resource data is upgraded to the Proven and Probable Reserve categories. Full public disclosure of gold production rates can only be provided once initial confirmatory underground exploration is completed and the appropriate regulatory filings are submitted and reviewed by the securities regulators.
d) Where is the serpentine?
Serpentine is located on the western-most edge of the property and in the old Idaho-Maryland underground mine workings, near Whispering Pines Lane.
e) What is the potential to add ounces (of gold)?
The potential to add gold ounces to our resource blocks is very good. Company geologists are confident that the current resource blocks can be expanded by underground drilling, and that known gold-bearing veins can be extended. Historically the bottoms of the veins of the Grass Valley District have never been reached, and so we have every reason to believe that these ore bearing veins will continue at depth.
a) What impact will the project have on Wolf Creek?
The water in the mine currently overflows into Wolf Creek near the southeast corner of the intersection of Idaho-Maryland and Centennial Roads. The mine water has a pH of about 7.5, which is quite neutral (pure water is 7.0). Our studies have shown that the geologic formation of the historic mine does not contain significant levels of heavy or toxic elements like arsenic. The mine will be dewatered via the New Brunswick shaft, collected and treated for elevated levels of iron and manganese that have been found in the water, then discharged into the South Fork of Wolf Creek. The water treatment system is designed to treat water to meet California Drinking Water Standards.
The volume of water removed from the mine will be mechanically controlled and will never pose any threats of creating flood conditions. During heavy rainy periods, pumping can be reduced or halted, if needed. Dewatering of the mine is planned for the first six to nine months of the project so that the mine workings at the 1300-ft level may be evaluated for gold resources before mining commences. We are planning on dewatering the mine to the 3280 level which is the deepest area in the existing mine workings.
b) Will there be measures in place to protect Wolf Creek from pollution?
Storm water runoff and water from dust control sprays will be captured in a detention pond on site before being discharged to Wolf Creek. There is no liquid discharge from the ceramic processing plant.
The water in the historic mine contains the minerals iron and manganese that will be removed by a water treatment plant before being discharged into the South Fork of Wolf Creek. Thus, the water entering the South Fork of Wolf Creek will be purer than the water now flowing in the creek.
c) Volumes of project water may be diverted to South Fork of Wolf Creek. What is the percent of the total currently in the creek and that which will be added that may raise the water level therein?
The Idaho-Maryland Mining Corporation has evaluated the narrowest section of the South Fork of Wolf Creek to address this matter. The dewatering rate of the mine through the New Brunswick Shaft is expected to be 6 cubic feet per second (cfs). The summer stream flow average is 0.68 cfs at a depth of .15 feet (ft), or 1.8 inches, and the winter stream flow rate is 5.5 cfs at a depth of 0.58 ft, or 7 in. Adding the mine water at a rate of 6.0 cfs to the summer flow average will bring the total flow rate to 6.68 cfs, creating a total depth of approximately six in. Adding the mine water at a rate of 6.0 cfs to the winter stream flow rate totals 11.5 cfs, creating a total depth of approximately 1 ft. The total depth of the narrowest point of the South Fork of Wolf Creek is approximately 4 ft, so there appears to be negligible impact associated with discharging the treated mine water to this tributary.
d) Concern was expressed about the potential of dewatering domestic wells.
For over ten years, the IMMC has studied the domestic wells situated in the New Brunswick Shaft area near the site of the proposed mine dewatering. These studies have been conducted with the permission of homeowners. It has been determined that the domestic wells penetrate an aquifer perched approximately 160 ft above the current water level in the mine. Since the two aquifers do not appear to be connected, once the lower aquifer that penetrates the historic mine begins to be dewatered, impacts to the local domestic wells in the upper aquifer are not expected. However, the contingent mitigation developed for potential impacts to domestic wells ten years ago, provision of connections to Nevada Irrigation District services, will be employed as part of the current project design as may be warranted.
a) What are the noise and vibration effects of dewatering?
None, the pump and motor will be set at 1400 ft deep below the surface and will not be heard from the surface. The submersible turbine pumps are very smooth running precision machines and will cause no vibration.
b) How do I sign up for the well monitoring program?
Call our office at 530-271-0679 and speak with our receptionist. If your home is located within our well study area she can send you a sign-up sheet. There will be no cost to you for participating in the monitoring program.
c) How will you give me temporary water?
If necessary we will place a temporary water tank on your property and we will make deliveries with a water truck to keep the tank(s) filled as needed to meet your normal water requirements.
d) Will you pay for Nevada Irrigation District water?
We will pay for the connection but you will be responsible for the monthly service fee.
e) Will bonds or public money be used to pay for well mitigation?
Bonds will be used to pay for well mitigation and will be posted by Idaho Maryland Mining Corporation. Public money will not be used to pay for well mitigation.
f) Will you be able to pump all of the water out of the mine?
From the Brunswick side of the mine, yes, however there may be water left in some of the underground shafts and lower areas in the Idaho part of the mine.
g) Will you pump continually?
We will pump continuously until the mine is dewatered. Once the mine is dewatered, we plan to store water underground during the day and pump to the surface at night during electrical off peak hours to save power costs.
h) What percentage of the water flowing from the Roto Rooter Building is the total for Wolf Creek?
Per telephone conversations with Nevada Irrigation District (NID), the NID conveys water in Wolf Creek at a rate of between 42 to 45 cfs during the irrigation season. That flow rate is in addition to the natural flow rate that is estimated to be between 3 and 5 cfs. So, the total flow rate is estimated to be between 45 cfs and 50 cfs during the irrigation season. After the irrigation season ends October 15thof each year, the flow rate is expected to drop considerably to 3 to 5 cfs until the first rains begin.
Historically, the mine accumulates water that discharges naturally at the East Eureka shaft collar (located near the Roto Rooter Building) at a rate of approximately 500 gpm (1.1 cfs) in the summer and 1200 gpm (2.7 cfs) in the winter. So, a worst case scenario is that if mine dewatering may remove 1.1 cfs (summer flow in October) from the low flow rate of 3 cfs, there will still be 1.9 cfs or 855 gpm in Wolf Creek.
From the assumptions noted above, the reduction at the Roto Rooter building during the summer is estimated to be about 2 percent, or 1.1cfs, as the Wolf Creek flow rate is approximately 48 cfs. During the winter, the flow rate in Wolf Creek, except during a storm event, may decline to about 24 cfs, so, the reduction of 2.7 cfs from the East Eureka shaft collar may be about an 11 percent reduction in flow.
For over ten years, the IMMC has studied the domestic wells situated in the New Brunswick Shaft area near the site of the proposed mine dewatering. These studies have been conducted with the permission of homeowners. It has been determined that the domestic wells penetrate an aquifer perched approximately 160 ft above the current water level in the mine. Since the two aquifers do not appear to be connected, once the lower aquifer that penetrates the historic mine begins to be dewatered, impacts to the local domestic wells in the upper aquifer are not expected. However, the contingent mitigation developed for potential impacts to domestic wells ten years ago, provision of connections to Nevada Irrigation District services, will be employed as part of the current project design as may be warranted.
b) Do you wait until my well goes dry to give water?
As soon as your well starts to become diminished we will implement the mitigation plan to replace your well with NID piped water. Hopefully we will have the piped water system operational before your well goes completely dry. If your well goes dry before piped water is available we will supply temporary water until the construction is complete and you are able to use piped water.
c) What is the plan for South Fork Wolf Creek when the project stops/reclamation?
A specific plan for the South Fork of Wolf Creek has not been submitted with the application as, per answer to Item V.A. f) indicates the project may impact it minimally, if at all. The plan will be developed during the EIR process, if necessary.
d) On-going discharge?
On-going flow from the mine will occur at an approximate rate of 500 gallons per minute (gpm) in the summer and 1200 gpm in the winter. These numbers are based on historical data from when the mine operated in the past.
e) Can we market water?
No, because we are not adding to the overall flow of Wolf Creek. We are just redirecting water from its current discharge location in Wolf Creek to the South Fork of Wolf Creek. At the confluence the water will flow back into Wolf Creek as it is now, so the net effect to flow in Wolf Creek below the confluence is zero.
f) What will the cost be to dewater?
Dewatering the mine will be expensive and will vary season to season and year-to-year depending on the dewatering rate and on electricity rates in effect during mine operations. The capital and operating costs to pump water from the mine have been taken into consideration when building our economic model.
a) Will you be heap leaching at the Idaho-Maryland site?
No.
b) Will the project rework the old tailings and clean up the site?
Existing tailings will be used for ceramics or, if needed, sent to a disposal facility.
A. Afternoon Session
a) How does ore enter the recovery process and slurry to separators, cyanidation and become gold concentrate?
The ore processing will be accomplished with a series of enclosed unit operations leading to the production of high quality ceramic products and gold doré. Industrial minerals and gold ore will be initially crushed underground before being transported by belt conveyor to the surface stockpiles or directly into the enclosed processing facilities. Non-gold-bearing rock will be crushed and finely ground to approximately 80 percent passing a 100-mesh (150 microns) size before being sent to the ceramics plant for processing.
Gold ore will also be crushed and ground to approximately 80 percent passing 100-mesh before entering a gravity gold recovery circuit that will recover most of the gold without the use of reagents. Further processing will involve the using a combination of flotation and cyanidation technologies.
Less than 15 percent of the ore will be treated with an intensive cyanidation process where small quantities of sodium cyanide (NaCN) solution will be used as a reagent to extract gold from the ore and gold concentrate. The NaCN dissolves the gold into a chemical solution in a highly monitored and closed processing circuit, which allows for the economic recovery of the gold by employment of an electro-winning (electroplating) technology. All un-reacted cyanide solution is recovered and recycled for reuse in the electro-winning process. There will be trace amounts of NaCN contained in some of the tailings, which will be reacted with sulfur dioxide gas to destroy the NaCN prior to final dewatering and transfer to the ceramics plant. The gold will be further recovered by smelting gold bearing sludge from electro-winning in a small electric furnace to produce gold doré (metal alloy) containing approximately 88 to 92 percent gold and the balance consisting of other precious and base metals) that will be sent to an offsite custom gold refiner for purification and sale as bullion.
b) What is the cyanide process?
See process description in a) above.
c) How will material processes be handled?
See process description in a) above.
d) Interest was expressed in the crushing machines and the ore recovery efficiencies.
Crushers
There will be three crushers in total. The primary crusher will be a jaw crusher which will be located underground. A jaw crusher is essentially two large flat plates set in a "V" configuration. One plate is stationary and the other plate is rocked back and forth against the fixed plate which crushes any rock dropped between the plates. It will be used to reduce ore size from roughly 12 inches (in) down to 3 in.
The secondary and tertiary crushers will be cone crushers. These crushers are made up of two nested, truncated cones orientated with the large end down. Feed material enters an annular gap between the upper, outer cone and the inner cone. The outer cone is stationary and the inner cone is rotated in an eccentric motion to crush ore between the two cones. Ore size reduction will be roughly 3 in. to ¾ in. for the secondary crusher and will be roughly ¾ in. to ¼ in. for the tertiary crusher.
Ore Recovery Efficiencies
For ceramics, our test work has indicated that we can expect an average feed material combustion or ignition loss of approximately 5 percent to 10 percent. No other production losses are anticipated as any products that do not meet quality standards will be recycled through the process. The overall ceramic recovery rate is anticipated to be in excess of 90 percent.
For gold, the Idaho-Maryland mine has historically achieved overall gold recovery efficiencies ranging from 94 percent to 97 percent. We anticipate we could achieve average gold recoveries in excess of 95 percent.
Flotation is a process that involves the addition of air to slurry and is used to concentrate the fine gold that was not separated by gravity concentration. The overflow slurry from the gravity concentrator is discharged into the flotation tanks where it is mixed with frothing reagents, and collecting reagents. The frothing reagents cause the air that is blown through the slurry to form small bubbles. The fine gold particles cling to the bubbles, which rise to form a froth of concentrated gold on the surface. The waste material or gangue settles to the bottom and is removed to the flotation tails thickener. The froth is skimmed off and sent through an intensive cyanidation process to dissolve the gold.
b) Cyanide process and potential of leaks was identified as a concern.
The intensive cyanidation system being considered for this project is a proven system safely used worldwide in dozens of gold processing operations for many decades. The system tanks are completely enclosed and will be located in a secured and high-curbed area specifically designed to completely contain any leakage. The system will also include a cyanide destruction circuit which reduces cyanide presence in the tailings to federal and state regulated levels. The Idaho-Maryland mine intends to adopt the International Cyanide Management Code and hence will be subject to periodic cyanide safety audits stipulated under the Code.
c) Back-up energy storage on-site to keep safety equipment from failing was raised as a concern.
There will be back-up generators located on all sites to ensure that safety equipment and key process equipment will be maintained in operation during any power outages.
d) What happens to cyanide after processing?
All un-reacted cyanide solution is recovered and recycled for reuse in the electro-winning process. There will be trace amounts of NaCN contained in some of the tailings, which will be washed and reacted with sulfur dioxide gas to destroy the NaCN prior to final dewatering and transfer to the ceramics plant.
c) Can you process the waste as fast as you pull it out to keep from stockpiling?
Yes, all rock brought to surface will be processed and there will be no waste material remaining on surface. There will, however, be stockpiles for operational purposes. During the initial construction of the decline, the rock brought to surface will be stockpiled temporarily until the ceramic plant has been constructed and put into operation. This stockpile is expected to be consumed within 2 years of ceramics plant startup. During normal operation, all rock brought to surface will be processed either for gold or be made directly into ceramic. The majority of the gold tailings will be made into ceramics and the remainder will be sent back underground as structural fill as required. Two small stockpiles of ore will be maintained for surge capacity to deal with variations between the ore-mining rate and processing rate.
A. Afternoon Session
a) How many employees will there be with the ceramics facility?
We are planning for the ceramics facility to eventually employ about 200 people.
b) Will materials be brought to site for processing?
We have made high-quality tiles from 100 percent Idaho-Maryland materials in our pilot plant and demonstration facility, and we expect that we will not need to bring in large quantities of other materials or additives to manufacture tile commercially here.
Glaze materials for tile will need to be brought in, but the quantity is small.
The Ceramexttm process works well on many other materials (such as ash from power plants, quarry fines, and slag from metallurgy), the primary purpose of the proposed ceramics facility in Grass Valley is to process material from the Idaho-Maryland Mine.
There will be no need to bring in additional feed materials in large quantities to Grass Valley.
Golden Bear Ceramics will likely build other processing plants elsewhere in the country to process fly ash, quarry fines, etc.
There may be future opportunities to use our process to take waste materials from local waterways like Greenhorn Creek or Rollins Lake, which would otherwise have to be trucked out of the area for disposal. This is technically possible, but not presently part of the plan to develop the Idaho-Maryland Mine.
c) Are there additives to the samples?
We have done some work with additives, but none of the samples we have shown the public have any additives. These samples are 100 percent Idaho-Maryland mine tailings, or 100 percent rock from our exploratory drilling. Some of the samples we have shown are coated with a ceramic glaze, but the underlying tile body has no additives. Colorants may be added to the body of the tiles to provide different base colors.
a) If Arsenic was within the ceramics product, what are the safety concerns?
Unlike Banner Mountain, the geology at the Idaho-Maryland mine does not have unusual levels of arsenic, so the feedstock to the ceramics plant will not have safety concerns with arsenic.
Ceramic tile made from other feedstock (for example ash from waste incinerators) may have higher levels of toxic metals. We are evaluating the safety concerns for eventually making ceramic tile (elsewhere) with those feed materials.
b) Heat dissipation from ceramics?
The ceramics process will use primarily gas heat. At its greatest extent of production (2400 tons/day), we expect the site to use 2,100 million cubic feet of natural gas per year. All of the heat generated eventually dissipates within the process into air.
Some residents recently asked if all this heat output was great enough to perceptibly raise the temperature in Grass Valley. The answer is no.
Even if we limit our calculation to just the space between Hwy. 49, Idaho-Maryland, Brunswick, and Bennett Roads that amount of heat cannot cause a perceptible increase in the local temperature.
c) Is there asbestos in the mine or the ceramics plant?
We expect that there may be some naturally occurring serpentinite, which can include fibrous asbestos materials, to be unearthed during mine operations. We will be able to quantify the amounts and locations of the serpentinite upon completion of the underground exploration work that will precede active mining operations. If extracted, the serpentinite may be included in the feed material to the ceramics plant or re-deposited in the mine as backfill. A substantial amount of serpentinite material can be tolerated in the ceramics feed as it would be destroyed at the manufacturing process temperatures.
As described in the Serpentinite Rock and Asbestos Summary Fact Sheet (Fact Sheet), the Idaho-Maryland Mining Corporation will develop an Asbestos Dust Control Plan upon completion of the CEQA process for the approval of the Northern Sierra Air Quality Management District prior to construction commencing. Therefore, dust control measures will be employed during surface and subsurface activities to ensure the protection of the community and employees. The Fact Sheet may be accessed electronically at the following location: Asbestos Serpentinite Fact Sheet
d) What happens if there is a natural gas outage?
A sudden gas outage would idle the ceramics plant in a safe mode, and would require reprocessing of 50 to 300 tons of material.
e) Is the process proven?
The CeramextTM process was first proven on a small batch scale (a few pounds per day). We have taken the process in the past year to a larger, continuous, development scale (about 500 pounds per day) and have proven it there. We are presently engaged in the next major scale-up of the process, which will prove it at rates exceeding 1 ton per day, and also will enable us to make and sell our first commercial product from our pilot and demonstration plant. The ongoing scale-up work presently directly employs 10 full-time engineering professionals or technicians at our Grass Valley development site.
The type of trees on site include: Ponderosa Pine, Cottonwood, Grey Pine, Madrone, Incense Cedar, Black Oak, White Alder, Walnut, Big Leaf Maple, Locust, Willow sp., Live Oak, McNab Cypress, Sugar Pine, and Douglas Fir.
b) What kind of trees will be affected?
The type of trees on site that will be affected include: Ponderosa Pine, Cottonwood, Grey Pine, Madrone, Incense Cedar, Black Oak, Big Leaf Maple, Locust, Live Oak, and Douglas Fir.
c) What trees will not be affected?
The site plans and tree locations were evaluated to determine the trees that will be directly affected by the construction (within a building, storage area, road or parking lot footprint). A second determination analyzed the trees that were adjacent to the construction activity to evaluate the extent of damage to the root zone of a tree. The health and condition of a tree is also factored into this second determination, as trees in poor or very poor condition are unlikely to survive impacts to the root zone environment.
Trees that are located outside of the impact zone of the proposed project will not be affected. Four thousand one hundred and twenty-nine (4,129) trees are located on sites that will not be affected by the proposed project. There may be small adjustments to this total (plus or minus) once the project is staked out and an onsite review of tree locations is completed.
d) Where is most of the project concentrated?
The project is concentrated on the Idaho Maryland Mine Site located between Idaho- Maryland Road and East Bennett Street.
e) What will happen to wood removed from the site?
No decision on the deposition of the wood from the project site has been made. A number of alternatives have been proposed at the public meetings and will be considered during the EIR process. The alternatives proposed include donating the wood to the Lutz Center Senior Wood Program or Habitat for Humanity. We are contacting both programs for donation criteria.
f) Can lumber be used for low-income housing?
We are contacting CDF and Habitat for Humanity for information on the type of wood (species) needed, size and timber harvest regulations with regard to this wood deposition alternative. This alternative will be addressed during the EIR review.
a) Concern was expressed about the loss of the treed view from Highway 49.
The mitigation for loss of screening will be determined during the EIR review. We are evaluating the site plan, the views from Hwy 49, the trees to be retained and sites for replanting.
b) The corner of Brunswick and Bennett is really ugly, can you make it a landscaped area or park?
The land immediately adjacent to the corner of Brunswick and Bennett is not owned by the Idaho-Maryland Mining Corporation and is owned by Sierra Pacific Industries. The Historical Ore Silo located off of Bennett Street near the intersection of Brunswick is located on one of three project properties. As the visible portion of the site at Bennett Street has in the past and will continue to be in the future, a paved entry and parking area, there may be little opportunity to enhance its curb appeal. However, we will evaluate various options to improve the appearance of the site during the EIR and Design Review processes.
c) What are the buffer zones for the riparian areas?
The buffer zone established by the City of Grass Valley that has been applied to the project design is 100 ft on either side of Wolf Creek and South Fork of Work Creek. The California Department of Fish and Game may designate a buffer zone during the CEQA project scoping process or upon receipt of a Streambed Alteration Notification from the Idaho-Maryland Mining Corporation after the City of Grass Valley completes the CEQA process.
d) Will large trees that need to be removed be replaced with large trees?
The most successful in-kind replacement is accomplished using trees that are grown in specialized containers that develop large root systems. The size of the root system is more important than the actual size of the replacement tree. Many unsuccessful mitigation efforts have been the result of planting large nursery grown trees that have been raised in pots that limit the size of the root system. Smaller trees with good root systems adjust to transplanting better than larger specimens, and in the long run, the smaller trees grow rapidly and typically will equal the larger tree size within five years.
Another factor to consider in replacement mitigation is the type of soil environment available for planting. In many cases, mitigation requires trees to be planted in areas where the environmental conditions will not support a particular species or for that matter, any tree at all. The determination of mitigation should consider the biological condition of the site and adapt the mitigation recommendations to ensure overall project success. This usually means developing alternative mitigation in addition to the typical tree replacement program, such as off-site mitigation and improvements to retained stands of trees to improve stand or habitat health and condition.
e) How was the "no wetlands" determination made?
MACTEC Engineering and Consulting, Inc. performed a Wetland Assessment for the Idaho-Maryland Mining Corporation in October, 2004 that is contained in Volume III, Appendix A of the Application. The Wetland Assessment was performed in accordance with the prescribed methodologies for delineating "Waters of the United States (U.S.)" and "wetlands" pursuant to the federal Clean Waters Act (CWA) and River and Harbors Act (RHA).
f) When was the last wetland determination and was it verified by the Corps of Engineers?
The Wetland Assessment was performed for the Idaho-Maryland Mining Corporation by MACTEC Engineering and Consulting, Inc. in October, 2004. As the purpose of the Wetland Assessment was to determine whether or not wetlands may or may not be present on the project site properties, it was not submitted to the U.S. Army Corps of Engineers (Corps) to be verified. As the City of Grass Valley has not yet permitted the proposed project, it would be premature to submit the project Wetlands Assessment to the Corps for verification. Once the permit is issued, it is expected that the Wetland Assessment will need to be revised and updated and submitted to the Corps for verification.
g) There are no natural communities stated in the application, how can that be?
MACTEC Engineering and Consulting, Inc. performed a Biological Screening Evaluation for the Idaho-Maryland Mining Corporation in February, 2004 that is contained in Volume III, Appendix K of the Application. The Biological Screening Evaluation was performed for the purpose of determining whether or not special status species were present on the three project sites. As more detailed analyses were envisioned to be conducted as part of the EIR process, natural communities, if any, are expected to be addressed in that environmental evaluation.
h) What will be done to mitigate tree loss?
The tree loss mitigation will be determined during the EIR review. As discussed in d), there are a number of mitigation possibilities. We are evaluating mitigation alternatives that would include replanting and improving existing natural community health.
i) Is there a tree ordinance?
Yes, the City of Grass Valley passed a Tree Preservation and Protection Ordinance in 2005.
j) Who will determine the mitigation of trees?
The City of Grass Valley will determine the mitigation during the EIR process.
k) How are the riparian wetland areas being assessed?
Please refer to answers provided for Question Nos. VI.A. c), VI.B. e), VI.B f), and VI.B. g).
a) Concern expressed of the annexation of county land to the City of Grass Valley.
Once annexed, the land currently administered by the County will be within the City's jurisdiction and the Idaho-Maryland Mining Corporation will pay taxes to the City and the County, as agreed upon during the annexation process.
b) Will this project be drug free and how will it be enforced?
Because of the dangers of working underground or on the surface around machinery, drugs and alcohol will not be tolerated and if found will be grounds for dismissal. Routine drug testing will be conducted, and supervisors will be trained to recognize physical indicators of drug and alcohol abuse.
c) Will the Idaho-Maryland try to acquire and mine adjoining mining claims in the future?
Perhaps.
d) Where does the gold go after it leaves the Idaho-Maryland and who buys it?
The gold produced at the Idaho-Maryland mine will be formed into doré bars, each weighing up to 50 lbs and are up to 90 percent pure gold. The bars will be shipped to a gold refining company to be upgraded to 99.5 percent purity for sales acceptance on commodities or metals exchanges. According to the World Gold Council, 51 percent of the "above ground gold" is consumed as jewelry, 19 percent is held as bullion by world central banks, 16 percent is held as bars or coins for investment purposes, and 12 percent used industrially primarily in electronics and dentistry.
e) Can I get a copy of the application on-line?
Yes, the permit application is posted on our website www.Idaho-Maryland.com.
f) What are the economics of tile vs. gold?
The price of gold (October 31, 2005) is $465/oz. If the grade of our ore is about 0.25 oz/ton, the value of our ore calculates to be about $116/ton. For the ceramics we can estimate an average gross of $1.25/square foot, which works out to a value of about $500/ton. So on a gross basis, tile can generate even more cash flow than gold. Costs for each process will vary, and depend of ore grade, production level, etc. The costs will determine which is more profitable, tile or gold.
g) Will the ceramics plant be ugly like that one in Lincoln?
Our plant will be different. It will be mostly enclosed in a single large building, with adjacent silos for storage of raw materials.
The large building will be a pre-engineered structure that will follow historical mining building architecture, however with a combination of near flat and gently pitched, multi-level roof line that will not exceed 50 ft in height. The roof and walls will be constructed of insulated steel panels and will be painted in accordance with the project color scheme. There will be several equipment and manned doors around the building. The east side of the building will have numerous roll up doors for forklift access for product load-out purposes. Translucent windows will be located along each length of building wall near the roof eave to augment interior lighting. Doors will be steel and windows will be plastic.
h) How tall are the silos?
The storage silos for the ceramics plant will be about 50 ft tall.
i) How does the gas price affect the economics?
Utility costs represent only about 20 percent of the production cost for the ceramics products, so increasing energy costs will have a limited effect on the profitability of the ceramics factory.
j) Will we have fuel on-site?
There are currently no plans to store or have fuel available on-site.
k) How to join citizen group?
Please join the list of citizens interested in providing input for this project, and being informed on an on-going basis about this project, by adding your name to the list of interested citizens via the Idaho-Maryland website: www.Idaho-Maryland.com, or call (530) 271-0679. To learn of other citizens groups that address community issues, please contact either Tom Last, Planning Director, or Joe Heckel, Community Development Director, at the City of Grass Valley at 530-274-4330.
l) Do we have to run 24 hrs. per day?
Current operations plans are to mine and operate the ore and ceramics processing plants 24 hrs a day.
A. Afternoon Session
a) How many jobs will there be with the project?
There are estimated to be up to 250 construction-related jobs. In addition there will be 200 jobs each in the mine and ceramics facilities; 400 total jobs in operations.
b) How many jobs will be for locals?
It is a policy of the Idaho-Maryland Mining Corporation to give preference to local labor, goods and service providers when feasible.
c) Who will be responsible for the occupational health personnel?
The Idaho-Maryland Mining Corporation will be responsible for retaining occupational health personnel to support the project.
d) What is the wage scale?
The average salaries at peak operation of the gold and ceramics operations, respectively, are estimated to be $65,000 and $45,000 (in 2004 dollars). The ranges of wages will be those representative of entry level to senior professional levels.
e) Will average taxpayer receive a reduction in taxes?
The Idaho-Maryland Mining Corporation does not make policies associated with tax rates and as such cannot answer the question.
f) Clarify roles of agencies. What is the relationship between City and County lands?
Two of the three properties associated with the project, the Idaho-Maryland and New Brunswick sites, are currently in the jurisdiction of the County but are located in an area called a "Sphere of Influence" for which the City has designated appropriate for annexation to within its jurisdiction. Because the sites are located within the City's Sphere of Influence, an annexation application was developed to facilitate that process between the City and County. The City and County will be working together in evaluating the project and making a determination on the appropriateness of the proposed annexation.
a) Does the City of Grass Valley have any assistance in the permitting process?
The Idaho-Maryland Mining Corporation is aware that the City is in the process of retaining consultants to assist in the permit application processing, evaluation of the Minerals Project Application and preparation of the Master Environmental Assessment and Environmental Impact Report. We have entered into a reimbursement agreement with the City to support the financial obligations that the retention of assistance represents.
b) Where can we get a copy of the Emgold Annual Report?
The Emgold Annual Report is available on-line at www.emgold.com. If you would like a copy mailed to you, please contact Emgold at 1-888-267-1400.
c) How many jobs will the project have, total?
There are estimated to be up to 250 construction-related jobs. In addition there will be 200 jobs each in the mine and ceramics facilities; 400 total jobs in operations.
d) Has the City of Grass Valley or the Idaho-Maryland contracted an economic assessment to be performed, such as that which the Cal State University at Chico can perform?
The Idaho-Maryland Mining Corporation contracted an economic impact study to be prepared by California State University at Chico for the project and it was contained in the July 2004 Conceptual Permit Application that was submitted to the City for consideration.
e) How will housing development be affected by project?
Based on the socioeconomic baseline analysis prepared for the study (contained in Volume III, Appendix M) there may be a demand for approximately 140 homes to support construction workforce and 220 homes to support operation workforce during the duration of the project. The total demand of 360 units represents 5 percent of the year 2000 housing in Grass Valley and 0.5 percent of the year 2000 housing in the County. At this time we are unable to determine if housing development will be affected by the project, as there are several Special Development Area project proposals that are under consideration by the City at this time.
f) Has there been an independent economic impact evaluation of the project by Cal State Chico?
The Idaho-Maryland Mining Corporation contracted an economic impact study to be prepared by California State University at Chico for the project and it was contained in the July 2004 Conceptual Permit Application that was submitted to the City for consideration.
g) Concern was expressed over the capacity of the City of Grass Valley to process the application and long-term oversight.
The Idaho-Maryland Mining Corporation is aware that the City is in the process of retaining consultants to assist in the permit application processing, evaluation of the Minerals Project Application and preparation of the Master Environmental Assessment and Environmental Impact Report. We have entered into a reimbursement agreement with the City to support the financial obligations that the retention of assistance represents. We understand that it is the intention of the City to diligently oversee the project.
h) Is the Surface Mining and Reclamation Act (SMARA) administered by the County of Nevada?
For this project, the City of Grass Valley will administer the SMARA as its land use policies and regulations have adopted that set of regulations to the satisfaction of the California Department of Conservation. If the permit applications were submitted to the County, it too, could administer SMARA as it has adopted that set of regulations in its land use policies and regulations to the satisfaction of the state Department of Conservation.
a) What are the effects of noise associated with these processes and that of trucking the material off-site (including traffic)?
The EIR will determine total traffic for future near term and long term conditions, to which project-generated traffic will be added. The "with and without project" near term and long term conditions analyses will allow the EIR noise analyst to address noise associated with the project's trucking of material off-site, in the context of future ambient noise conditions.
b) Transport of cyanide in trucks on highways (e.g., over Donner Pass) was raised as a concern.
Transport of cyanide will be conducted in accordance with hazardous substances policies administered by the U.S. Department of Transportation, U.S. Environmental Protection Agency, California Department of Transportation and Environmental Protection Agency.
c) How many trucks per day is 600 tpd and 2400 tpd?
An average truckload will be 20 tons, so 600 tons per day is 30 trucks per day. At 2400 tons per day, we expect 120 trucks per day.
A. Afternoon Session
a) What will be the traffic routes and times?
Daily Trip Generation
On a typical weekday there should be about 595 inbound and 595 outbound auto and truck trips associated with all facets of the proposed project, while on a Saturday or Sunday there should be about 475 inbound and 475 outbound auto and truck trips. Trip generation on a weekend day will be about 20 percent less than during a weekday, primarily due to fewer administrative staff, visitors and other nonscheduled trips on a Saturday or Sunday.
On a weekday, about 128 of the 595 inbound or outbound trips will be made by large trucks, which will be about 22 percent of the total project weekday traffic. On a weekend day, about 120 of the 475 inbound or outbound trips will be made by large trucks, which will be about 25 percent of the total project weekend day traffic.
Peak Hour Trip Generation
The project applicant has set shift change times for all activities that will, to the maximum extent possible, limit project auto and truck traffic on the local roadway network between 7:00 and 9:00 AM, noon to 1:00 PM and 4:00 to 6:00 PM. All shift changes, other than for half of the mining and ceramics administrative staffs, have been moved to other time periods.
1. Employee & Visitor Traffic
Employee traffic during a weekday morning commute period will be expected to total about 32 inbound and two outbound auto trips from 7:00-8:00 AM, with two inbound and three outbound auto trips from 8:00-9:00 AM. The peak inbound flow of traffic to the project coming from Marysville, Auburn, Colfax and the I-80 corridor will be traveling in the off-peak travel directions on the Route 20, 49 and 174 state highways. During a weekday evening commute period, employee and visitor traffic will be expected to total about five inbound and 35 outbound auto trips from 4:00-5:00 PM, with two inbound and one outbound auto trips from 5:00-6:00 PM. The peak outbound flow of traffic from the project going to Marysville, Auburn, Colfax and the I-80 corridor will be traveling in the off-peak travel directions on the Route 20, 49 and 174 state highways. Auto traffic during the noon lunch hour is projected to be 13 inbound and 14 outbound trips.
In addition to expected employee shift changes, visitor and delivery activity, it is also likely that there will be an ongoing minor level of unscheduled project auto trip generation, primarily during daylight hours, associated with employee trips to/from local businesses, restaurants, etc.
2. Truck Traffic
Project truck traffic during the commute periods will be comprised of three to six inbound trucks per hour for hauling ceramics (with an average of five trucks per hour). Ceramics transport trucks will be 30- or 40-ton GVW flatbed or enclosed tractor-trailers. Inbound trucks will be empty. All outbound ceramics trucks (which will be full) will be held at the project site between 7:00-9:00 AM and 4:00-6:00 PM. Based upon the capacity of proposed loading facilities, only five to six ceramics trucks per hour will be loaded. Inbound truck patterns will remain somewhat constant throughout a 24-hour period, with an average of five trucks during most hours and an estimated low of three to four trucks per hour expected leading into the first hour of the morning or evening commute periods, when loaded trucks will beheld on-site until 9:00 AM or 6:00 PM. At most, six trucks would be expected traveling inbound to the ceramics plant during any given hour. Outbound truck distribution patterns over a 24-hour period will be somewhat different than inbound patterns. The project sponsor's prohibition of outbound truck trips from 7:00 to 9:00 AM and 4:00 to 6:00 PM will result in a larger than average amount of truck traffic leaving the project site from 9:00 to 11:00 AM and from 6:00 to 8:00 PM (an estimated eight to 12 trucks per hour). For all other hours during the day, there should be an average of about five outbound truck trips per hour.
Projections of daily and peak hour trips have also been included in Volume III, Appendix N in the Application documents
b) Is there to be a control over the traffic routes?
Inbound and outbound truck traffic would be restricted to use of Idaho-Maryland Road between the S.R.20/49 freeway and Centennial Drive, which would lead directly to the project's truck access driveway. Almost all truck traffic would be expected to travel to and from the west (south) on the S.R. 20/49 freeway. All project employee and visitor traffic would be expected to use the East Bennett Road corridor, with most accessing the downtown Grass Valley freeway interchange. Overall, during the AM peak hour the project would be expected to add about 31 vehicles to East Bennett Road west of the site and five vehicles (trucks only) to Idaho-Maryland Road between Centennial Drive and the freeway, while during the PM peak hour the project would be expected to add about 34 vehicles to East Bennett Road west of the site and five vehicles (trucks only) to Idaho-Maryland Road between Centennial Drive and the freeway.
c) Will there be easy access to the freeway?
Planned freeway access is described in item b), above.
d) What is the total number of trucks per day?
On a weekday, about 128 of the 595 inbound or outbound trips will be made by large trucks, which will be about 22 percent of the total project weekday traffic. On a weekend day, about 120 of the 475 inbound or outbound trips will be made by large trucks, which will be about 25 percent of the total project weekend day traffic.
e) Will there be congestion at Highway 49 and Brunswick?
Current projections show, at most, 10 to 15 percent of project employee traffic during the AM and PM peak commute traffic hours (i.e., a total of 4 inbound vehicles during the AM peak commute traffic hour and 6 outbound vehicles during the PM peak commute traffic hour) using Brunswick Road to access the project site. No project truck traffic would be routed to or from this direction.
The majority of project employee trips will be expected to travel to and from the site via Bennett Road west to S.R. 20/49, while all project truck trips will be routed via Idaho-Maryland Road to S.R 20/49.
f) Will there be pedestrian trails associated with the project?
Yes. However, trail locations have not yet been determined.
g) What air quality effects from traffic will there be?
Air quality impacts may result from traffic generation and will be explored in the EIR for this project.
The truck routes to Reno have not yet been established. The Idaho-Maryland Mining Corporation is conducting additional studies to address this issue that will be available at another of their public workshops in the future.
b) What will the impacts be on all Highways -- 49, 174, and 20?
The traffic analysis conducted to date has considered project trip generation and distribution, only. Impact analysis for future Near Term and Long Term conditions will be among the subjects addressed in the EIR traffic analysis for this project.
c) Road repairs and upkeep?
The project will be expected to participate in its "fair share" of roadway repair and upkeep. This will be presented in the EIR for this project, and further defined in the EIR Monitoring Plan.
d) Who will build the proposed road going through property on the General Plan?
The City of Grass Valley's General Plan shows a future roadway connection between Idaho-Maryland Road and East Bennett Road. The exact location of the future roadway connection and alignment have not been determined, however, it is expected that this issue will be better defined through the EIR for this project.
e) What route and times will trucks take?
Please refer to the response to item VIII. A. a), above.
f) How many trucks travel roads right now and then add Idaho-Maryland trucks?
Total existing and future truck volumes on Idaho-Maryland Road will among the subjects explored in the EIR traffic analysis for this project.
Project-generated truck volumes are addressed in the context of total project traffic in response to item VIII. A. a), above.
g) Accident concerns on Bennett Road between Diamond Court and Brunswick?
Accident data and concerns regarding auto, truck, bicycle and pedestrian safety for Bennett Road will be among the many topics addressed in the EIR for this project.
No, the pump and motor will be set at 1400 feet deep below the surface and will not be heard from the surface. The submersible turbine pumps are very smooth running precision machines and will cause no vibration.
b) Noise of process plant was raised as a concern.
All of the primary crushing will ultimately occur underground. In the initial phase of the project, a portable primary crusher may be used at the Idaho-Maryland site. Secondary crushing would occur inside the mill building, where the noise would be controlled to meet occupational standards.
c) Will underground crushing make vibrations and noise neighbors can detect?
At this time it is uncertain whether or not neighbors may detect noise and vibration. It is expected that this matter will be addressed during the EIR process.
A. Afternoon Session
a) Will underground blasting and vibration cause subsidence?
Underground blasting will be controlled to move relatively small amounts of rock in a manner that will protect the integrity of the mine as well as to ensure the safety of the mineworkers. Therefore we do not expect the intensity of blasting to be perceptible or annoying to aboveground observers.
b) What will the noise level be in the New Brunswick area?
The noise sources of potential concern in the New Brunswick area are the aeration blowers associated with the water treatment plant. These will incorporate inlet silencers, and will be installed in enclosures. Noise produced by these units will have to meet the standards of the Grass Valley Noise Element, including consideration of any tonal content. We are currently collecting the data necessary to prepare a detailed noise study for these pumps, and will report back to you with the results.
c) What is estimated about the truck noise?
Predictions of traffic noise levels have included the projected truck activity. In general, the project would generate less truck traffic than that envisioned by the Grass Valley General Plan, since the total number of truck-generating businesses would be fewer than projected. As a result, overall traffic noise levels in the future would be lower with the project than without it. However, future traffic noise levels would be 3 to 5 dB higher than existing noise levels in either case. This would be a noticeable change, but would occur with or without the project.
d) Where will most noise be generated?
Most of the noise sources included in the project (on-site vehicles and air pollution control equipment) would be associated with the Idaho-Maryland site. The only noise sources at the Round Hole and New Brunswick sites would be fans and pumps.
e) What are the effects of atmospheric conditions on noise attenuation?
Under certain atmospheric conditions, such as temperature inversions and wind shear, noise from distant sources can become audible. For example, area residents can often hear highway traffic noise better at night than in the day, usually because a temperature inversion "bends" the sound back down towards the ground. Also, wind can carry sound downwind so that sounds from distant sources become audible. These effects usually occur thousands of feet from the noise source, so that the sound levels are relatively low. The resulting sounds, though audible, are typically well below usual noise standards.
The noise sources of potential concern in the New Brunswick area are the aeration blowers associated with the water treatment plant. These will incorporate inlet silencers, and will be installed in enclosures. Noise produced by these units will have to meet the standards of the Grass Valley Noise Element, including consideration of any tonal content. We are currently collecting the data necessary to prepare a detailed noise for these pumps, and will report back to you with the results.
b) What work hours for crushing?
Crushing could occur at any time of the 24-hour day.
c) What is the impact on the surface of blasting, vibration and crushing?
Underground blasting will be controlled to move relatively small amounts of rock in a manner that will protect the integrity of the mine as well as to ensure the safety of the mineworkers. Therefore we do not expect the intensity of blasting to be perceptible or annoying to aboveground observers. Crushing does not typically produce perceptible vibration beyond 50-100 feet from the unit, since the crushers are usually suspended on springs.
d) In the Bennett Street area near Amethyst Court, will truck and fork lift noise be sources of noise?
Noise level predictions were made for the homes at Cordell Court, immediately west of Amethyst Court. The noise of forklifts operating during nighttime hours at the ceramic stockpiles was identified as a potential impact at Cordell Court. Noise levels at Amethyst Court would be lower due to the additional distance. If noise is mitigated to meet the Grass Valley standards at Cordell Court, the noise levels at Amethyst Court would also be in an acceptable range.
e) Is crushing underground and on the surface?
All of the primary crushing will ultimately occur underground. In the initial phase of the project, a portable primary crusher may be used at the Idaho-Maryland site. Secondary crushing would occur inside the mill building, where the noise would be controlled to meet occupational standards.
f) Is there an existing facility that we could measure noise level?
There is no local existing facility from which noise measurements may be taken.
g) Noise travels; how far will it go day or night?
Under certain atmospheric conditions, such as temperature inversions and wind shear, noise from distant sources can become audible. For example, area residents can often hear highway traffic noise better at night than in the day, usually because a temperature inversion "bends" the sound back down towards the ground. Also, wind can carry sound downwind so that sounds from distant sources become audible. These effects usually occur thousands of feet from the noise source, so that the sound levels are relatively low. The resulting sounds, though audible, are typically well below usual noise standards.
h) What does 50 dB noise mean?
50 dB is a relatively low level, and this value is commonly used as a daytime average noise standard in rural areas. The noise produced at the vents of an air-conditioning system in a large office building or a meeting room is often in the range of 50 dB.
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