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When coal surfaces are exposed, pyrite comes in contact with water and air and forms sulfuric acid. As water drains from the mine, the acid moves into the waterways; as long as rain falls on the mine tailings the sulfuric-acid production continues, whether the mine is still operating or not. [15]
Ideally, coal slurry consists only of crushed coal and water, which can be efficiently separated. In practice, the separation is significantly costly due to the large amounts of water needed and wastewater generated by the process. [8] Furthermore, the slurry consists also of very fine coal dust that results in a waste called blackwater.
A newer commercial use for pyrite is as the cathode material in Energizer brand non-rechargeable lithium metal batteries. [20] Pyrite is a semiconductor material with a band gap of 0.95 eV. [21] Pure pyrite is naturally n-type, in both crystal and thin-film forms, potentially due to sulfur vacancies in the pyrite crystal structure acting as n ...
Jul. 24—STEWARTVILLE — As Stewartville Public Schools gets ready to ask voters for a large infusion of funding this fall, it first had to decide how to differentiate its request from the ...
The water cycle including human activities. Water cycle management is a multidisciplinary approach relating to all planning, developmental, operational and tactical decisions to influence the water cycle. Most importantly water cycle management is used to ensure availability of clean water for designated use, and to ensure safe release of ...
Iron pyrite (FeS 2), which is relatively plentiful in the gold ores of the Witwatersrand, oxidises to insoluble ferric oxide (Fe 2 O 3) and sulfuric acid (H 2 SO 4). Thus, when mine waste comes into contact with oxygenated rainwater, sulfuric acid is released into the ground water.
The use of sophisticated sensing equipment to monitor air quality is common and has replaced the use of small animals such as canaries, often referred to as "miner's canaries". [ 29 ] In the United States, the increase in technology has significantly decreased the mining workforce. in 2015 US coal mines had 65,971 employees, the lowest figure ...
The five principal technologies used to monitor and control water flow at mine sites are diversion systems, containment ponds, groundwater pumping systems, subsurface drainage systems, and subsurface barriers. In the case of AMD, contaminated water is generally pumped to a treatment facility that neutralizes the contaminants. [25]