Acid Mine Drainage - Essay Example

? ACID MINE DRAINAGE 0 This paper exclusively looks into the process of Acid Mine Drainage, AMD; it defines the ADM and gives what necessitate the process as well as the factors that accelerate the process. It do recognizes that AMD is one of the environmental threats in the offing as most of the economies are hinged in the process of mining’s that contributes a huge chunk of income to the struggling economies of any states in the world. In such it discusses all the possible avenues with which AMD can emerge and gives in depth analysis with regard to the chemical composition, reaction and eventual production of the AMD. This paper also strives to give in summary different sources of the AMD and the appropriate remedies that can be put into practice to quench the lethal problems associated with AMD. In the same breadth, it discusses the health related problems associated with AMD as well as those of ecological. This paper can be of meaningful help to those who work in the mines and risk contracting the problems linked with the site. When the precautionary measures that are discussed in this paper are stringently followed by the concerned individuals with the appropriate technology and man power, there is no doubt the problem of the AMD will be a thing of the past. 2.0 Introduction Acid mines drainage (AMD) is one of the major environmental threats that comes as a result of extraction of minerals for economic purposes. If these mines are not properly managed, then the exercise of extraction results into a serious environmental menace. Essentially acid mines drainage is a peculiar kind of a wastewater that that results from the continuous processes of weathering as well as leaching of coal and metalliferrous compounds that contain sulphur as an element in them. The various activities of mining for example, strip and underground mining exposes the sulfide (pyrite) and other metallic compounds that incorporate sulphur to a level of oxidation given the availability of oxygen and water. The oxidation process will increase the acidity level i.e. low P.H value, as the value of the P.H decreases, the oxidation process of the metals equally increases increases and this significantly reduces the water quality and culminate into water pollution (Drever 133). The formation of the acid mines drainage process can also be facilitated by through biological processes. The microorganism thiobaccillus ferroxidants is an acid tolerant microbe and is known to be associated with acid mines drainage sites as it enhances the oxidation of the compounds that contain sulphur compounds (Drever 147). . The resultant water in the acid mines drainages are very hazardous to health, in that the acidity and the components of water from the mines contain lethal chemicals. As stated above, without the buffering processes of the process, the acidity level will exponentially increase accelerating weathering process and subsequent development and continuation of the acid mines drainages (Drever 151). 3.0 Origin of Acid Mine Drainage Several factors can bring about development of the acid mines drainages, coming into contact between the surface water (oxygenated) with the pyritic ores is one of the ways that largely contribute to the formation of the acid mines drainage. This interaction takes place in three different ways; when the mining processes change the direction of flow of the water pattern to areas endowed with rocks that have been in constant touch with the ground water that is anoxically stagnant (Berner and Berner 98). The other possibility is when the spoils form the pyritic mining is disposed in an area of percolating oxygenated water, and when the pyritic minerals waste materials are directly discharged into the aquatic environment. 4.0 Results The formation of the acid mines drainages results into several environmental degradative processes that are vey detrimental to the survival biological life, in such, measures are always put into place as precautionary obligation to ensure that the negative sides of the mining do not surpass the positives. In a round up, the formation of the acid mines results into any of the following; the high acidity realized in the AMD coupled wit the presence of the heavy metals realized during oxidation of the pyrites when access the aquatic environment can lead to serious chronic health problems when consumed by man or other animals (Berner and Berner 103). The oxidation of iron metals in the AMD leads to the formation of a coat that inhibit infiltration of the sunlight in aquatic environment leading to hindrance of photosynthesis in the benthic organism. The acidity of the AMD also reduces the absorption of carbon dioxide and this may lead to serious ecological crisis as some of the organisms in the ecology with have not to undergo some important physiological processes breaking their importance in the ecology- the essence of the ecological niche is lost (Berner and Berner105). The above picture shows the pyrite, also known as ‘fools gold’. It is a prerequisite for the formation of AMD through oxidation. AMD Assessment The above picture illustrates the area under which the assessment was done, the assessment aimed at establishing whether there is contamination of the river by the mining activities that is taking place in along the river. The need for the assessment was necessitated by the sporadic increase in acute infection of the population that uses the water form the river. These even become salient regarding the fact that only the population downstream after the mine adit and its wastes was contracting these infections. The hypothesis of the study was that the establishment of the mine in the area has led to the contamination of the water from the river and the subsequent acute infection. Having known the effects of the acid mine drainage that was primarily suspected to be the cause of the problems, a number relevant of tests were taken in pursuit of the same. The results of the test taken were recorded and documented as shown below; Site Flow (L s-1) P.H Fe Mg L-1 Al Mg L-1 Cu Mg L-1 Z n Mg L-1 R1 240 6.9 0.40 Fe3+ + OH- The F3+ can then remain viable to take part in the oxidation reaction of the pyrite as shown below. FeS2 + 14Fe3+ + 8H2O => 15Fe2+ + 2SO42- + 16H+ This reaction is the one the is responsible for the production of high volumes of acidity The diagram below shows a scenario of a typical AMD, the flow of the affluent can be vividly observed and in the case that they find their way into the aquatic life, they can pose great danger. In the event that the AMD is cause by the spoilt heap and the mines discharged into aquatic life, then a remedy through bioremediation process can be advanced to rectify the situation. In the event that it’s instigated by the spoilt heap and mine waste discharges then the following can be the best remedy; 5.1 Engineered Chemical Treatment In this case, a solution of the alkali is mixed with the AMD. The reaction that will follow will raise the P.H and subsequently remove the presence of the heavy metals in the solution. 5.2 Initiation of Artificial Wetlands When artificial wetland is started with the introduction of microbial, then the physiological processes of the microbes will raise the P.H and the problems of the AMD will cease. In fact, this is the cheapest way of giving a remedy to AMD (Domenico and Schwartz 140). In the case of the spoil heaps that produce AMD, the following can be done; Inhibition of the AMD production through killing the bacteria, this is possible by the introduction of the biocides that will ensure that the nexus between the bacteria and the production of the AMD is disconnected. Introduction of the phosphate into the system will also inhibit the AMD as the phosphate will form a complex with the F3+ making it scarce for further oxidation. Finally, the system can also be deprived of the oxygen which is very essential in oxidation to halt any progress in the formation of the AMD (Domenico and Schwartz 132). Reference List Drever, J.I. The Geochemistry of Natural Waters, surface and groundwater environments, Third Edition, Prentice-Hall, 1997.  Berner, R.A. and Berner, E.K. The global water cycle, geochemistry and environment, Prentice-Hall, 1987.  Domenico, P. and Schwartz, F. Physical and chemical hydrogeology , Second Edition, 1997, John Wiley and Sons.  Younger, P.L. Banwart, S. A. and Hedin, R.S. 2002 Mine water, hydrology, pollution, remediation, Kluwer Academic Publishers Read More