Appalachian USA coal mines have been implicated as major stressors to aquatic life in headwater streams via discharge of total dissolved solids(TDS).This paper summarizes column leaching studies of spoils(n>50)and ...Appalachian USA coal mines have been implicated as major stressors to aquatic life in headwater streams via discharge of total dissolved solids(TDS).This paper summarizes column leaching studies of spoils(n>50)and refuse and TDS effects on local water quality and biotic response.The initial pH of most materials is near-neutral.Initial specific conductance(SC)values range from 500-1,000 to >3,000 μs/cm,but 2/3 of materials drop below 500 ls/cm after several pore volumes of leaching.Studies of mining-influenced streams have found altered aquatic life,relative to natural conditions with no mining influence,at SC ranging from-200 to-700 ls/cm with depressed aquatic life consistently associated with elevated TDS;mechanisms causing such effects are under investigation.We suggest that active mine operations should be modified to place high TDS producing materials in ways that reduce contact with percolating drainage waters.展开更多
The Sabodala gold mine is located in the Kedegou region in eastern Senegal near the border with Mali in a tropical Savannah climate zone with distinct wet and dry seasons. The mine has been operating since 2009 with a...The Sabodala gold mine is located in the Kedegou region in eastern Senegal near the border with Mali in a tropical Savannah climate zone with distinct wet and dry seasons. The mine has been operating since 2009 with active tailings deposition giving an ideal opportunity to study the weathering characteristics of carbonate rich tailings materials under real world conditions. The mine is operated in accordance with international best practice with regular monitoring of water quality and tailings chemistry in accordance with the international cyanide management code (ICMC) and also in order to monitor and control any potential impacts from Acid Rock Drainage and Metal Leaching (ARDML) that may be generated from the tailings materials and waste rock. In 2015 as part of a project looking at the potential for re-use of generated tailings as construction materials, a number of additional geochemical tests including whole rock assays, mineralogy, Acid Base Accounting in accordance with modified Sobek method with siderite correction, together with paste pH and electrical conductivity (Ec) measurements were undertaken. The purpose of the study was to update the predictions of the potential for ARDML generation and drainage pH in leachates forming from the Sabodala tailings. The tests were run on one composite weathered and 3 selective fresh samples collected by auger drilling on three holes over the tailing. Results have enabled a better understanding of the chemical weathering characteristics of finely ground tailings materials under tropical weathering conditions and the nature of secondary minerals precipitated.展开更多
基金supported by a wide array of sponsors including the Powell River Project and the USDI Office of Surface Mining Applied Science ProgramAportion of the work reported was also sponsored by the Appalachian Research Initiative for Environmental Science(ARIES).ARIES is an industrial affiliates program at Virginia Tech,supported by members that include companies in the energy sector.
文摘Appalachian USA coal mines have been implicated as major stressors to aquatic life in headwater streams via discharge of total dissolved solids(TDS).This paper summarizes column leaching studies of spoils(n>50)and refuse and TDS effects on local water quality and biotic response.The initial pH of most materials is near-neutral.Initial specific conductance(SC)values range from 500-1,000 to >3,000 μs/cm,but 2/3 of materials drop below 500 ls/cm after several pore volumes of leaching.Studies of mining-influenced streams have found altered aquatic life,relative to natural conditions with no mining influence,at SC ranging from-200 to-700 ls/cm with depressed aquatic life consistently associated with elevated TDS;mechanisms causing such effects are under investigation.We suggest that active mine operations should be modified to place high TDS producing materials in ways that reduce contact with percolating drainage waters.
文摘The Sabodala gold mine is located in the Kedegou region in eastern Senegal near the border with Mali in a tropical Savannah climate zone with distinct wet and dry seasons. The mine has been operating since 2009 with active tailings deposition giving an ideal opportunity to study the weathering characteristics of carbonate rich tailings materials under real world conditions. The mine is operated in accordance with international best practice with regular monitoring of water quality and tailings chemistry in accordance with the international cyanide management code (ICMC) and also in order to monitor and control any potential impacts from Acid Rock Drainage and Metal Leaching (ARDML) that may be generated from the tailings materials and waste rock. In 2015 as part of a project looking at the potential for re-use of generated tailings as construction materials, a number of additional geochemical tests including whole rock assays, mineralogy, Acid Base Accounting in accordance with modified Sobek method with siderite correction, together with paste pH and electrical conductivity (Ec) measurements were undertaken. The purpose of the study was to update the predictions of the potential for ARDML generation and drainage pH in leachates forming from the Sabodala tailings. The tests were run on one composite weathered and 3 selective fresh samples collected by auger drilling on three holes over the tailing. Results have enabled a better understanding of the chemical weathering characteristics of finely ground tailings materials under tropical weathering conditions and the nature of secondary minerals precipitated.
