Coal: Construction and Mining Impacts
Construction and mining activities that may cause environmental impacts include ground clearing, grading, excavation, blasting, trenching, vehicular and pedestrian traffic, and drilling.
Typical activities during the construction and mining phase include ground clearing (removal of vegetative cover and topsoil), drilling, blasting, trenching, excavation, and vehicular and pedestrian traffic. Activities conducted in locations other than the facility site include construction for transport systems (including access roads, rail lines, and/or conveyor systems). Potential impacts from these activities are presented below, by the type of affected resource.
The following potential impacts may result from construction and coal mining activities.
Primary sources of noise during construction and mining would include equipment (draglines, augers, rollers, bulldozers, pile drivers, and diesel engines) and blasting. Other sources of noise include vehicular traffic and other transport systems (rail or conveyor systems). Whether the noise levels exceed guidelines established by the U.S. Environmental Protection Agency (EPA) or local ordinances would depend on the distance to the nearest residence. If near a residential area, noise levels from blasting and some equipment operation could exceed the EPA guideline but would extend for a limited amount of time.
Air Quality (including Global Climate Change and Carbon Footprint)
Emissions resulting from construction and mining activities include vehicle emissions; diesel emissions from large construction equipment and generators; carbon monoxide, nitrogen oxides, and particulates from blasting activities; possible releases of methane, hydrogen sulfide, and coal dust through the venting of shaft mines; and fugitive dust. Fugitive dust would be caused by:
A permit is needed from the state or local air agency to control or mitigate these emissions; therefore, these emissions would not likely cause an exceedance of air quality standards nor have an impact on climate change. A transportation conformity analysis may be required in non-attainment areas.
There is also the potential for fires to erupt and burn uncontrollably in the coal seams. This can result in the shutting down of the mine. The air emissions from a fire could exceed air quality standards.
Direct impacts to cultural resources could occur from construction and mining activities, and indirect impacts might be caused by soil erosion and increased accessibility to possible site locations. Potential impacts include:
Ecological resources that could be affected include vegetation, fish, and wildlife, as well as their habitats. Adverse ecological effects could occur during construction and mining from:
Site excavation, along with construction of access roads and support facilities, could reduce, fragment, or dramatically alter existing habitat in the disturbed portions of the project area.
During construction and mining, ecological resources would be most affected by the disturbance of habitat in areas near the mine, support facilities, and access roads. Wildlife in surrounding habitats might also be affected if the mining activity (and associated noise) disturbs normal behaviors, such as feeding and reproduction.
Acid mine drainage affects water quality and would therefore affect aquatic and wildlife species dependent on that water supply and their habitats.
If significant impacts occurred in any resource areas, and these impacts disproportionately affected minority or low-income populations, then there could be an environmental justice impact. It is anticipated that the development could benefit low-income, minority, and tribal populations by creating job opportunities and stimulating local economic growth via project revenues. However, a number of issues of potential concern could disproportionately affect minority or low-income populations during construction and mining, including noise, air quality, health and safety, the possibility of relocation, subsistence impacts (impacts to plants, fish, and wildlife used as sources of food), water quality, destruction of cultural sites and traditional use areas, and visual impacts from the mine site and possible impacts associated with the construction of new access roads.
Hazardous Materials and Waste Management
Waste generated from mining and coal preparation activities includes waste rock and coal refuse. Waste rock includes rocks that have little or no practical mineral value, but are present above the coal seam and are excavated during surface mining operations along with the overburden. Coal refuse is the rejected material (e.g., slate, clay, sandstone, shale, siltstone) that occurs adjacent to the coal seam and is removed during the preparation and washing of the coal. About 75% of the coal refuse is stockpiled, but approximately 25% is very fine (less than 2 millimeters) and is discarded in slurry form.
Solid and industrial waste would also be generated during construction and mining activities. The nonhazardous solid wastes would consist mostly of containers, packaging materials, and wastes from equipment assembly and construction crews. Industrial wastes would include minor amounts of fuels and spent solvents and maintenance-related wastes (e.g., used oils and hydraulic fluids, spent coolants, battery electrolytes, and dielectric fluids). Hazardous materials from coal processing may include coal wastes containing lead and mercury. These hazardous materials would be transported off-site for disposal, but impacts could result if the wastes were not properly handled, and were released to the environment.
Human Health and Safety
Potential impacts to worker and public health and safety from coal mining would be similar to those expected for construction projects that employ blasting, significant earthmoving, and using large, oversized equipment. Blasting generates fugitive dust and can also release nitrogen oxide, dependent on the geological materials present where the explosives are set. Underground mining has additional risks, such as possible oxygen deficiency, potentially hazardous (and explosive) atmospheres (methane, hydrogen sulfide, coal dust), collapse of walls or roofs in the mine, or the flooding of a mine if an aquifer is breached. An additional potential health impact from underground mining is pneumoconiosis, a lung disease resulting from prolonged exposure to coal dust (also called "black lung disease"). In addition, health and safety issues include working in potential weather extremes and possible contact with natural hazards, such as uneven terrain and dangerous plants, animals, or insects. The Mine Safety and Health Administration heavily regulates mining activities to best ensure the safety of mine workers.
Impacts to land use could occur during construction if there were conflicts with existing land use plans and community goals; conflicts with existing recreational, educational, religious, scientific, or other use areas; or conversion of the existing commercial land use for the area.
During construction and mining activities in underground mines and strip mines, impacts to most land uses would be temporary, such as removal of livestock from grazing areas during blasting or heavy equipment operations, or temporary effects on the character of a recreation area due to construction noise, dust, and visual intrusions. For these types of mines, long-term land use impacts would occur if existing land uses are not compatible with coal mining, such as residential use or remote recreational experiences; however, those uses could potentially be resumed if the land is reclaimed to pre-development conditions. The potential for future subsidence of underground mines could also create long-term land use impacts.
For open pit mines, land use impacts could be significant in that the landscape would be much more difficult, and in some cases impossible, to reclaim to pre-development condition.
Indirect impacts to livestock, agricultural practices,, and subsistence resources could also occur if water quality is affected by mining operations, such as through acid mine drainage or sedimentary or other contaminant runoff concerns.
Impacts to paleontological resources could occur directly from the mining activities or indirectly from soil erosion and increased accessibility to fossil locations. Potential impacts include:
Direct beneficial impacts would include the creation of new jobs for workers, and the associated income and taxes paid, as well as any royalties. Indirect beneficial impacts would occur as a result of the new economic development, and would include new jobs at businesses that support the expanded workforce or provide project materials, and associated income and taxes.
Adverse impacts could occur as a large in-migrant workforce, culturally different from the local indigenous group, could strain the existing community infrastructure and social services. Some economic losses could occur if recreationists (including hunters and fishermen) avoid the area. Mining activities could also potentially affect property values, either positively from increased employment effects or negatively from proximity to the mine site and any associated or perceived adverse environmental effects (e.g., noise, visual, air quality, etc.).
Soils and Geologic Resources (including Seismicity/Geo Hazards)
Sands, gravels, and quarry stone would be excavated for constructing access roads; for concrete for possible ancillary structures; and for improving ground surface for lay-down areas and equipment staging areas.
Possible geological hazards (such as earthquakes and landslides) could be activated by excavation and blasting, increasing slopes during site grading and construction of access roads, altering natural drainage patterns, and toe-cutting bases of slopes. Altering drainage patterns could also accelerate erosion and create slope instability.
Surface disturbance, heavy equipment traffic, and changes to surface runoff patterns could cause soil erosion and impacts to special soils (e.g., cryptobiotic soils). Impacts of soil erosion could include soil nutrient loss and reduced water quality in nearby surface water bodies.
Increases in the use of local roadways and rail lines could occur during the mining period. Oversized loads could cause temporary transportation disruptions, and could require some modifications to roads or bridges (such as fortifying bridges to accommodate the size or weight). Shipment weight might also affect the design of access roads for grade determinations and turning clearance requirements. Heavy equipment would remain at the site.
Possible sources of visual impacts during construction and mining include:
Water Resources (Surface Water and Groundwater)
Water would be used for dust control when clearing vegetation and grading, and for road traffic; for supporting drilling activities; and for consumptive use by the construction crew. This water could be trucked in from off-site, depending on local availability of groundwater wells or surface water sources. Water would also be needed to support coal washing activities occurring in the coal preparation plant. Water supporting the preparation plant activities would likely be obtained from local groundwater wells or nearby surface water bodies, depending on availability.
Water quality could be affected by:
Surface and groundwater flow systems could be affected by withdrawals made for water use, wastewater and stormwater discharges, and the diversion of surface water flow for access road construction or stormwater control systems. Excavation activities and the extraction of geological materials could affect surface and groundwater flow. The interaction between surface water and groundwater could also be affected if the surface water and groundwater were hydrologically connected, potentially resulting in unwanted dewatering or recharging of water resources.