Acid rock drainage naturally occurs when sulfursulfide ores are in contact with water and oxygen. Acid mine drainage in australia department of the environment. Acid mine drainage handson experiments to test for acidmine drainage earth science week. The quality of the drainage water emanating from an acid generating rock pile also varies, depending not only on the presence or absence of acid generation, but on the rate of acid generation, hence amount load of acidity produced rate of leaching, hence concentration of acidity in leachate history of acid product accumulation and. Acid rock drainage ard, also referred to as acid mine drainage amd, is the outflow of acidic water from mining operations including waste rock, tailings. Sulfides, when exposed to oxygen and water, oxidise to produce sulfates and acid. Acid rock drainage as a concern and part of all metals and mining operations.
Acid mine drainage patagonia area resource alliance. Acid mine drainage terms acid mine drainage amd water that is polluted from contact with mining activity acid rock drainage ard natural rock drainage that is acidic both produce acidic waters how to distinguish. Amd is caused when water flows over or through sulfurbearing materials forming solutions of net acidity. Kendra zamzows presentation slides as a pdf file dr. Acid rock drainage analysis and testing services acid rock drainage ard also known as acid mine drainage amd describes the formation of acid when sulphidebearing mine wastes principally pyrite, but also pyrrhotite and chalcopyrite are exposed to oxidising conditions, typically in the presence of water, due. Commonly referred to as acid rock drainage ard or acid mine drainage amd, acid drainage from mine waste rock, tailings, and mine structures such as pits and underground workings is primarily a function of the mineralogy of the rock material and the availability of water and oxygen. The acid runoff further dissolves heavy metals such as copper, lead, and mercury into groundwater or surface water. The most significant environmental impact from mines results from minerals that weather and release potentially harmful elements into water resources. Sulfide or sulfur must be present for acid to form. Acid base accounting is a test to assess the potential of a material to. Acid mine drainage, rock drainage, and acid sulfate soils. An introduction to acid mine drainage wv department of.
Acid mine drainage amd refers to the outflow of acidic water from a mining site. Illustrated with dozens of photographs, charts, tables and maps, the book is a compendium of 36 scientific papers written by various experts that cover these complex topics. Project overview and background on sulfideacid rock drainage issue. Acid mine drainage is caused by both abandoned mines and mines in current excavation. Acid mine drainage mines built as early as the 1800s were developed in a manner which utilized gravity drainage, to avoid excessive water accumulation in the mines as a result, water polluted by acid, iron, sulfur and aluminum drained away from the mines and into streams results of acid mine drainage. The proposed highway 1169 eagles nest lake area improvement project is located in rural st. Acid mine drainage ferric iron acidithiobacillus ferrooxidans permeable reactive. This chapter also provides a description of the sulphide oxidation process, including the biological, chemical, and physical factors that govern sulphide oxidation, control migration of ard, and that modify the.
Acid rock drainage prediction manual mend project 1. Mar 19, 2014 learn about how acid can naturally be generated from rocks exposed at the earths surface. Acid rock drainage ard is produced by the oxidation of sulfide minerals, chiefly iron pyrite or iron. Acid rock drainage ard prediction is a very important issue in order to predict and prevent environmental pollution associated with mining activities. Handson experiments to test for acidmine drainage earth. Comparison of acid mine drainage microbial communities in physically and geochemically distinct ecosystems. Treating acid mine drainage from abandoned mines in remote areas. Acid mine drainage and its control measures submitted by. Bibliography for acidrock drainage and selected acidmine. Acid rock drainage ard refers to the acidic water that is created when sulfide minerals are exposed to air and water and, through a natural chemical reaction, produce sulfuric acid. The sulfuric acid causes leaching of iron, manganese, lead, copper, zinc and cadmium from the rock it interacts with. Drainage from surface or deep coal or metal mines and coal refuse piles. This is a natural chemical reaction which can proceed when minerals are exposed to air and water.
Illustrated with dozens of photographs, charts, tables and maps, the book is a compendium of 36 scientific papers written by. Innovative treatment technologies purpose currently there is no comprehensive survey about the types of remediation technologies being used to treat abandoned mines. Prepared in cooperation with the tennessee department of transportation. Heavy metals emanating from former mine sites are a major threat to water resources. Section 3 survey of acid mine drainage at mine sites in australia pdf 846. This profound shift in weathering regimes beginning at 2. Acid rock drainage analysis and testing services acid rock drainage ard also known as acid mine drainage amd describes the formation of acid when sulphidebearing mine wastes principally pyrite, but also pyrrhotite and chalcopyrite are exposed to oxidising conditions, typically in the presence of.
Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. Evolution of acid mine drainage formation in sulphidic mine. Acid mine drainage results when surface and ground water combine with sulfuric rock from the mines, causing a sulfuric acid. Pdf acid mine drainage formation, control and treatment. These chemical and biological reactions can generate acidic waters which increase the potential for the. Any dissolved metal leached from the rock will hydrolyze when it comes into contact with water, and will produce acid brick 1998. Acid rock drainage ard is the outflow of acidic water from mining operations including waste rock, tailings, and exposed surfaces in open pits and underground workings. Acidrock drainage at skytop, centre county, pennsylvania, 2004. Geological survey open file report 20051148 online version 1. Acid rock drainage ard also known as acid mine drainage amd describes the formation of acid when sulphide bearing mine wastes principally pyrite, but also pyrrhotite and chalcopyrite are exposed to oxidising conditions, typically in the presence of water, due to groundwater, rain and runoff. Pennsylvania, acidic drainage involves iron sulfide minerals such as pyrite and its exposure to air to create iron oxides and acidic water.
When rock is exposed to weathering, it will release minerals as it comes into equilibrium with its environment brick 1998. Ard is often mislabelled amd or acid mine drainage too. The purpose of this paper is to provide information about this topic with a particular focus on hard rock mining sites. Acidrock drainage at skytop, centre county, pennsylvania, 2004 technical report pdf available january 2005 with 370 reads how we measure reads. Sulfatereducing bacteria srb present a natural way to reverse the damage caused by acid mine drainage. Also learn about the impact of construction projects on this phenomenon. Acid rock drainage ard is the natural result of oxidizing or.
Strong acid is made when certain bacteria populate the ore. Acid mine drainage prediction compares acid rock drainage factors of waste rock piles and tailings impoundments. Some bedrock contains minerals that can generate acid rock drainage ard. Acid mine drainage, acid and metalliferous drainage amd, or acid rock drainage ard is the outflow of acidic water from metal mines or coal mines acid rock drainage occurs naturally within some environments as part of the rock weathering process but is exacerbated by largescale earth disturbances characteristic of mining and other large construction activities, usually within rocks. Acidbase accounting is a test to assess the potential of a material to. Aerobic bacterial pyrite oxidation and acid rock drainage. Project overview and background on sulfide acid rock drainage issue. The development of the global acid rock drainage gard guide is sponsored by inap with the support of the global alliance. Naturally occurring acute acid drainage is uncommon in pennsylvania. This pdf of the gard guide can be downloaded and printed. Acid rock drainage ard is the natural result of oxidizing or rusting of certain types of sulfurbearing minerals in the presence of water, air and bacteria. Formation, impacts, and remediation of acid rock drainage how does acid rock drainage start. Pdf acid mine or acid rock drainage jorge g ibanez.
Potential environmental health impacts in alaska recorded 43014. Kendra zamzows presentation in a clickable version to see animations. Assessment of acid rock drainage and metals release. Under acid conditions a wide range of metals are more soluble.
Acid mine drainage terms acid mine drainage amd water that is polluted from contact with mining activity acid rock drainage ard natural rock drainage that is. Acm acid consuming materials are materials with capacity to neutralise acid. In every significant case, it is the exposure of iron sulfides to air by dropping the water table or excavating rock, the lack of any inherent buffering capability, and the flow of water through the rocks that create acidic drainage. The acid mine drainage may also contain high amounts of co2 which forms carbonic acid and further depresses the ph. Pdf acid mine drainage amd occurs after mining exposes metal sulfides to oxidizing conditions. In this lecture we discuss weathering, acid rock drainage and methods for prevention and mitigation. In every significant case, it is the exposure of iron sulfides to air by dropping the water table or excavating rock, the lack of any. Acid mine drainage effects, types, plants, marine, oxygen. In most cases, this acid comes primarily from oxidation of iron. The waste from cyanidation is a fine rock solution that is. The resulting leachate is known by several terms, including acid and metalliferous drainage, acid rock drainage and acid mine drainage.
Acid mine drainage amd is typically characterized by low ph and high dissolved iron. Treating acid mine drainage from abandoned mines in. Price canmet, natural resources canada smithers, british columbia abstract a large number of mines throughout the world are faced with the high cost and technical challenges associated with ard mitigation. Fact sheet acid mine drainage the problem the formation of acid mine drainage and the contaminants associated with it have been described as the largest environmental problem facing the u. List of potential information requirements in metal leachingacid rock drainage assessment and mitigation work.
In examining this table, it is important to note that diffusion of oxygen into water is slow and, therefore, oxidation of iron sulfide is inhibited until the water level drops, which can occur periodically or seasonally in some cases. Nowadays, simple tests are widely applied and established in the mining and consulting business for ard prediction. When fully exposed to air and water, the chemical reactions forming amd occur at a faster rate. Despite general agreement on the significance of acid mine drainage at. Development of the global acid rock drainage guide. Learn about how acid can naturally be generated from rocks exposed at the earths surface. Typically in nova scotia, ard occurs when pyrite and other sulphide minerals are exposed to water and oxygen, and react in a chemical oxidation process that releases sulphuric acid and metal oxides into watercourses downstream. Acid rock drainage and acid mine drainage acid rock drainage ard is a natural process in which sulfuric acid is produced when sulfides in rocksfor example. Acid metalliferousmine drainage management abbreviations and definitions acronym term definition determination unit aba by sobek the acidbase accounting test was developed in 1974 to evaluate coal mine waste and was modified et al. Acid metalliferousmine drainage management abbreviations and definitions acronym term definition determination unit aba by sobek the acid base accounting test was developed in 1974 to evaluate coal mine waste and was modified et al. The document applies to the complete life cycle of mining, from exploration to mine closure, and environmental management practices are recommended to mitigate the identified environmental concerns. There are four chemical reactions that represent the chemistry of pyrite weathering to form acid mine. Key engineering considerations would include seepage genera.
The objective of this paper is to use four different. The environmental code of practice for metal mines describes operational activities and associated environmental concerns of this industrial sector. Use of multivariate statistics in order to understand the. An in situ ftir study of galena and pyrite oxidation in aqueous solution. Acid mine drainage control technologies are measures that can be undertaken where. In colorado alone there are over 30,000 abandoned mines. Acid rock drainage and metal leaching at the pebble prospect. Acid mine drainage solutions for the mineral industry. Ard has the potential to introduce acidity and dissolved metals into water, which can be harmful to fish and aquatic life.
Acid mine drainage overview acid rock drainage ard is produced by the oxidation of sulfide minerals, chiefly iron pyrite or iron disulfide fes2. Chapter 2 presents an introduction to acid rock drainage ard, the history of ard, and an overview of ard processes and definitions. Acm acid consuming materials kgh 2so 4ton afp acid formation potential kgh 2so 4ton amd acid metalliferous drainage the generic term acid mine drainage is used to describe the low ph subset of mine drainage. During mining, the coal and associated strata containing varying amounts of sulfide minerals commonly pyritefes2 are exposed to atmospheric oxygen. Acid rock drainage from sulphide minerals is the most significant environmental impact from mines. Appendix g assessment of potential for acid mine drainage. Mining waste and the generated acid rock drainage containing sulphuric acid and trace elements constitute a serious threat to surface waters in regions with mining.
The global acid rock drainage guide pdf about 126 mb. Acid mine drainage prevention and control options 601 prediction of performance the performance of the designed or selected options compared to the adopted standards is predicted by applying appropriate engineering techniques e. Highly acidic water with elevated levels of dissolved metals. So, to better understand amd and ard, lets begin by defining some terms like ph the standard measure of acidity. The physicochemical oxidation reactions which produce acid drainage can be further accelerated by biological activity involving bacteria. In order to be able to effectively minimize the impact from mining waste it is important to find, understand and treat the major paths for the contaminant water from source to. Sgs laboratories offer complete ard testing services that help predict acidic effl uents. The problem of acid rock drainage acid rock drainage ard, often referred to as acid mine drainage ard, can be defined as the drainage that occurs as a result of natural oxidation of sulphide minerals contained in rock which is exposed to air and water. Geologic units containing potentially significant acid. For the proper understanding of the formation of acid mine drainage. Guideline document for monitoring acid mine drainage. Pure neutral water has a ph of 7, acids have a ph less than 7 and. This is a natural chemical reaction which can proceed. The ph scale actually measures hydrogen ion concentration in water solutions.
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