Frequently Asked Questions
- When will people living in the project area have a chance to comment on the proposed mine plan?
- How will fish and fish habitat be affected? Is there a plan to minimize these effects?
- What will be the effect of mine operations on caribou and other wildlife and habitat in the project area?
- How will acid generation from the pyritic tailings be prevented both during and after operation?
- Will the water that flows through the tailings impoundment be allowed to drain into surface waters after mine closure?
- What engineering controls are used to prevent leaks or collect leakage from embankments?
- How will the tailings be prevented from blowing away?
- Why was the south tributary of the Koktuli River chosen for tailings disposal?
- What will be the chemical composition of water draining from the mine environment after the operation closes?
- If the pit lake water is contaminated or acidic, how will this water be prevented from entering the downstream environment?
- What effects will the Pebble Project have on the quality of drinking water in the project area?
- How high is the risk that drinking water sources could be contaminated by the Pebble operation?
- What will The Pebble Partnership do to ensure that drinking water quality is not changed?
- During the life of the operation and beyond, what will The Pebble Partnership do to assure subsistence resource consumers that their resources have not been contaminated?
- Of the various alternatives for power that are being considered, which is projected to have the lowest air quality impact?
- How will dust be controlled in the mine environment?
- How high is the risk that water could be contaminated by the Pebble operation?
- What will The Pebble Partnership do to ensure that water quality is not changed in the downstream environment?
- Is The Pebble Partnership doing studies to evaluate the relative risk to commercial fishery damage?
- Will effluent be allowed to pass from the tailings pile or from the mine into the groundwater table, or will there be linings that prevent effluent movement?
- We are concerned about, and wonder if you can demonstrate, whether three years of baseline collection of environmental and socioeconomic data will be adequate for all ecosystem components, especially caribou migration and surface water hydrology as it relates to salmon spawning and rearing?
- The Pebble Partnership studies to assess the baseline use of subsistence resources, if somehow attained by the wrong hands, such as unethical hunting guides, could be used to the detriment of subsistence users. How is this information kept confidential through a public process and in perpetuity?
- A large population increase due to employment requirements would add demands for schooling, medical facilities, police force, fire departments and other services beyond effects this could have on subsistence, environment and wildlife. Who is going to pay for services that will have to be developed or expanded?
1. When will people living in the project area have a chance to comment on the proposed mine plan?
The Pebble Partnership is actively seeking input on its mine development proposal - now and in the future. You can provide us with your thoughts by calling 1-877-293-2600, entering your comments on our website (www.pebblepartnership.com), or attending community meetings on the Pebble Project.
2. How will fish and fish habitat be affected? Is there a plan to minimize these effects?
It's not yet known how the proposed Pebble mine might affect fish and fish habitat in the project area. The process of selecting a preferred mine development plan is ongoing, with a primary goal of avoiding and minimizing effects on fish and fish habitat. Any effects that ultimately cannot be avoided will be mitigated to ensure that productive fish habitat in the project area is maintained.
3. What will be the effect of mine operations on caribou and other wildlife and habitat in the project area?
We will be better equipped to assess associated risks once we've collected our baseline data and defined the project. We do, however, recognize that subsistence is a core value and way of life for people living near the project area. Our consultants are conducting extensive studies, including interviews with residents, to better understand any possible impacts and inform our engineering team as mine planning efforts progress. We also recognize that long-term monitoring of all potential impacts to wildlife in the project area must be part of our overall mine plan.
4. How will acid generation from the pyritic tailings be prevented both during and after operation?
The Pebble Partnership is currently investigating a mill design option that would separate the tailings that have pyrite in them from the materials that do not so that, once separated, these pyritic materials could then be stored under water (sub-aqueous) to prevent acid generation.
Pyrite by itself does not "cause" acid to form, but it is a necessary ingredient. "Pyritic" or "reactive" tailings have pyrites in them, and when these materials are exposed to water and air at the same time the potential for acid formation exists. Therefore, just segregating reactive tailings doesn't prevent acid formation. They must be stored such that they are not exposed to water and air at the same time. It is The Pebble Partnership's intention to store these potentially reactive tailings under water during operation, and the residual pond left after operation will continue to cover the reactive part of the tailings, thereby protecting against acid generation and ensuring acceptable water quality conditions.
5. Will the water that flows through the tailings impoundment be allowed to drain into surface waters after mine closure?
After mine closure, any water discharge would meet "Aquatic Life Standards". It is too early in the project design process to know the details of how this discharge would be managed. Study results, together with engineering design work will provide the necessary information at a later date.
The Pebble Partnership is required by regulatory agencies to develop a "Reclamation Plan" for the Pebble Project before making application for permits to construct and operate the mine. It is likely that the Reclamation Plan will have some features and attributes common, but not identical, to plans for other mining projects. Some of these "typical" features are:
- If the quality of the water that will accumulate on the tailings area meets the "Aquatic Life Standards" then these waters would be directed to the existing natural drainage or it would be allowed to accumulate in a constructed wetland before being directed to the existing natural drainage.
- If the quality of the water that accumulates on the tailings area does not meet the "Aquatic Life Standards", then these waters would be directed to a water treatment facility, which would paid for, in perpetuity, by the bonds that the company would provide as a permit requirement. The clean water leaving the facility would meet "Aquatic Life Standards".
6. What engineering controls are used to prevent leaks or collect leakage from embankments?
Tailings embankments do not "leak" in the usual sense of the word. Seepage is allowed to occur in a planned and controlled manner. This seepage actually strengthens the embankment which is a feature of embankment design in areas where seismic activity is expected.
In these cases, embankments are constructed with a "zone" of very low permeability material (resistant to passing water) in the embankment core, with a zone of coarser materials with higher permeability placed on the downstream side of the core. Water moving through the embankment is greatly retarded, but not completely blocked, by the low-permeability core. Water that does get through enters the higher permeability filter zone, where it drains to a seepage collection and recovery system. This seepage water follows the route of least resistance, which is down. From this area, the seepage water is typically collected and pumped back into the tailings facility. In some cases, when seepage water meets water quality objectives, it is released to the environment. While the water quality in the tailings facility is expected to meet Aquatic Life Standards, release to the environment during mine operations is not currently anticipated for the Pebble Project.
7. How will the tailings be prevented from blowing away?
The main way to keep tailings from blowing away is to keep them wet during operations and covering them at closure.
Tailings are initially deposited in the disposal area in a slurry (about 70% liquid) through spigots (special release points built into the tailings pipeline). Once the tailings slurry is discharged, the solid material begins separating from the water, creating a very low-gradient (flat) "beach" extending into the disposal area. This is much like the delta deposits of large glacial rivers. The coarser materials separate from water first, and remain higher on the beach. The smaller, lighter fractions, stay with the water until they reach the pond, and then they also settle out. Since the slurry discharge is rotated between many different spigots, the sandy "beach" remains wet.
Closure techniques are also employed. The wet tailings are bound together by small water droplets through a process called "capillary tension". If the tailings are allowed to dry out and these capillary tensions are removed, they would be more susceptible to wind erosion. Techniques that are used successfully at many other mine operations include maintaining a water cover, establishing an ice cap in winter, or covering dry tailings with a layer of non-erodible rockfill, topsoil or vegetation.
8. Why was the south tributary of the Koktuli River chosen for tailings disposal?
The south fork of the Koktuli River (east of Kaskanak Mountain) is being considered for tailings disposal, because the company's preliminary integrated engineering, environmental and socioeconomic analysis indicate that this area would have the least risk of all the possible alternatives.
Currently this general location is favored by The Pebble Partnership, but feasibility level engineering, environmental and socioeconomic analyses are still going on. Once these studies have been completed, The Pebble Partnership plans to discuss the selection process with communities to ensure that important information has not been missed. This consultation process will have a significant bearing on the final selection of the best alternative.
This area is favored for several reasons. First, the area is reasonably close to the mine and mill, and tailings can be efficiently deposited here. Second, compared to neighboring areas, overall environmental risks are low at this site. Third, unlike neighboring areas, this area does not support "robust" populations of fish and wildlife species, especially salmon. In general, although some other available areas would likely be cheaper to build, operate and maintain, this general area would involve the least environmental risk, and it appears feasible to build.
9. What will be the chemical composition of water draining from the mine environment after the operation closes?
Water that would leave the site after the operation closes would meet the "Aquatic Life Standards" set by state and federal authorities.
If water does not meet Aquatic Life Standards, it would have to be treated in a Treatment Plant paid for by a bond posted by the mining company as part of the permitting requirements, and released only if Aquatic Life Standards are met after treatment. If water treatment is necessary, it would continue as long as needed to ensure Aquatic Life Standards are met.
10. If the pit lake water is contaminated or acidic, how will this water be prevented from entering the downstream environment?
Pit optimization studies are still underway. When the work is completed and data assessed, this question, which is high on the list of design considerations, will be answered in a complete manner.
The pit would be deep enough, however, that in the beginning, it would be the downstream environment, i.e. all adjacent waters would tend to flow into the pit. How these inflows will be managed is still being studied and investigated. The pit would have to be virtually full before any nearby stream or pond would be "downstream" (or "down-gradient"). Any water leaving the pit lake, by whatever route (groundwater or surface water) must meet conservative Aquatic Life Standards. If pit lake water did not meet Aquatic Life Standards, it would have to be collected and treated in a treatment plant before leaving the mine area.
11. What effects will the Pebble Project have on the quality of drinking water in the project area?
None. The Pebble Partnership is undertaking a broad range of studies on water quality and water flows in the project area to assess the project's potential effects on water resources. If studies show that local well or other sources of drinking water could potentially be affected, steps will be taken to avoid and minimize project effects on water and to maintain a safe and reliable supply of drinking water throughout the life of the mine.
12. How high is the risk that drinking water sources could be contaminated by the Pebble operation?
The risk posed by the Pebble Project to drinking water sources downstream is extremely low. Further details will be available once the feasibility study and environmental studies have been completed.
13. What will The Pebble Partnership do to ensure that drinking water quality is not changed?
If there is any determination that drinking water would be significantly affected as a result of the project design proposed by The Pebble Partnership, permits would not be granted.
To make sure that drinking water quality is protected, the design of the facilities and operations will be such that contaminants do not leave the project area, either in surface water or in ground water. The Pebble Partnership has been working diligently on designing both the mill capacity, called "through-put", and the tailings storage facility footprint to achieve the proper water balance. This means that the amount of water used in the mill process and stored within the tailings facility is balanced with the amount of precipitation and runoff within the project footprint. The current goal is to have no excess water to discharge any time during mine operations. After operations, the closure plan, which is required as part of the permitting process, would have to include specific provisions for routing runoff and making sure that any water leaving the project would, at a minimum, meet relevant aquatic life and human consumption standards, including, if necessary, the use of a water treatment facility. This exists as a requirement under both state and federal regulations.
14. During the life of the operation and beyond, what will The Pebble Partnership do to assure subsistence resource consumers that their resources have not been contaminated?
The Pebble Partnership has already started an extensive monitoring program for such resources as plants (emphasizing those used for subsistence) and soils. Background monitoring data now being collected will be compared to monitoring data collected for the life of the mine (and beyond, as determined by regulatory agencies and in accordance with permit conditions).
15. Of the various alternatives for power that are being considered, which is projected to have the lowest air quality impact?
The proposal that is projected to have the lowest air quality impact is the one that provides power from the Rail Belt Grid via the Kenai Peninsula.
Homer Electric, the company conducting the feasibility analysis on power demand, has indicated that there will be surplus power available to supply the Pebble Project and that if additional power generation is required they will be able to meet the Pebble's usage requirements. There will be the need for emergency power in the event of a power failure and that is envisioned to be through the use of diesel generation.
16. How will dust be controlled in the mine environment?
"Fugitive dust", has two potential sources: from concentrate production and road traffic. Water is typically used to control dust from mining and tailings processes at most mining operations. Fugitive dust would be controlled by specific handling procedures to keep it from being available to escape into the environment.
Water applied by dedicated water trucks, and similar other techniques are expected for the Pebble Mine. The design considerations have not been completed for Pebble however, so the recommended approach has yet to be developed. The use of alternative dust palliatives will also be assessed to determine their efficacy in dust mitigation and to ensure they do not cause other environmental impacts.
The details of how the concentrate is to be handled have not been developed as yet, and thus a decision on whether it will be transported by truck or a slurry pipeline has not been made; further detailed studies are currently being conducted to assist in making this decision. However, in other operations, where fugitive dust is effectively controlled, they typically transfer concentrate in a negative pressure environment (within a building) where the concentrate is placed into containers equipped with covers. Trucks and their trailers are not permitted to enter the transfer buildings. As a secondary precaution, to protect against dust from road traffic, trucks are washed before leaving the mine site.
17. How high is the risk that water could be contaminated by the Pebble operation?
The risk is extremely low. The Pebble Partnership is designing the project to ensure that any water discharged from the site would meet, at a minimum, the required "Aquatic Life Standards".
Various modern mine design features and operational controls utilized in mine operation, in addition to the requirements for strict Quality Assurance & Control processes dictated by the permitting process, provide multiple levels of refinement and review for the purpose of ensuring that water resources are protected.
18. What will The Pebble Partnership do to ensure that water quality is not changed in the downstream environment?
The Pebble Partnership will be required to design the mine in a manner that would ensure that all discharges to the environment meet water quality standards - otherwise permits would not be granted.
19. Is The Pebble Partnership doing studies to evaluate the relative risk to commercial fishery damage?
Yes, however it is too early in the design process to provide specific details about these studies.
Protection of the aquatic resources and "no project induced net loss to the Bristol Bay Regional fisheries" is a fundamental objective of The Pebble Partnership. The Pebble mine can be developed, operated and closed/reclaimed without creating risk to the fisheries of the region. The importance of this resource is recognized and it is understood that it will be necessary to demonstrate that it can not only be protected once the mine development proceeds. The Pebble Partnership is and will be conducting numerous studies to demonstrate these objectives are achievable.
20. Will effluent be allowed to pass from the tailings pile or from the mine into the groundwater table, or will there be linings that prevent effluent movement?
Any water, associated with mine processes, leaving the mine site would have to meet strict "Aquatic Life Standards" that have been developed by state and federal authorities.
The Pebble Partnership is still in the early stages of design such that the details for managing the water on the site have not yet been fully developed. Concepts that are being considered for this site include seepage control and collection measures that would be most appropriate for the control and management of seepage and spills that might occur. There are a variety of seepage control techniques that could be used: such as low permeability synthetic liners, seepage cutoff walls, grouting in bedrock along with seepage recovery and recycle systems such as engineered drains and pump-back well systems.
As the details of the design become known they will be shared with all stakeholders.
21. We are concerned about, and wonder if you can demonstrate, whether three years of baseline collection of environmental and socioeconomic data will be adequate for all ecosystem components, especially caribou migration and surface water hydrology as it relates to salmon spawning and rearing?
We are aware of the concern over the number of years of baseline data, but given the intensity of the field and laboratory effort, and the scrutiny with which the environmental documentation and permit applications will be reviewed, the data set will be very robust - even for a project of this size and complexity. The Pebble Partnership and its consultants have already collected an impressive amount of information on a wide number of environmental topics including surface hydrology, groundwater hydrology and salmon spawning and rearing use for all three of the major watersheds in the vicinity of the Pebble Project, as well as most of the tributary streams near the potential project footprint. Wildlife data collection is also continuing and The Pebble Partnership expects that the database for caribou migration, moose winter areas and other resource species will also be robust especially when local and traditional knowledge are incorporated.
In the end, the baseline database collection process will be as long as it needs to be in order for the Federal and State Agencies to determine the permitability of the Pebble Project. Regulatory agencies and other stakeholders will have ample opportunity to review baseline data and provide input and critical comments throughout the environmental documentation, permit application and NEPA processes. The Pebble Partnership is purposely engaging in an extremely open pre-application process so that early comments can be received and acted upon. The company continues to encourage all stakeholders to become constructively engaged in making Pebble an environmentally responsible project.
22. The Pebble Partnership studies to assess the baseline use of subsistence resources, if somehow attained by the wrong hands, such as unethical hunting guides, could be used to the detriment of subsistence users. How is this information kept confidential through a public process and in perpetuity?
This information is truly confidential and is held in confidence by the consultant and the provider. Even though The Pebble Partnership is commissioning the studies neither we, nor anyone else, will be given the details of the study.
The Pebble Partnership expects to receive a general statement about subsistence resources and their use by those who use them and nothing more. Even that information will only be released if the providers agree.
23. A large population increase due to employment requirements would add demands for schooling, medical facilities, police force, fire departments and other services beyond effects this could have on subsistence, environment and wildlife. Who is going to pay for services that will have to be developed or expanded?
Our base assumption is that 100% of The Pebble Partnership employees will be housed at a remote camp and that consequently we anticipate no impact on the local services.
The Pebble Partnership employees are prohibited from hunting and fishing in the Bristol Bay Region. Accordingly, The Pebble Partnership does not anticipate that Pebble Project will place pressure on the local medical, emergency services, schools or subsistence and wildlife.
The Pebble Project will have an emergency services plan for the operation such that proper response can be given to those who might require medical attention, either because of accidents or personal health incidents. At this time the planning for this has not been completed but it will be part of the feasibility study.
It is possible that a mine emergency plan would be coordinated with that of the region, so that in the even of a community emergency that so required, the Pebble team would respond and visa versa.
