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case study of the Environment issues Assignment
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Added on 2021-05-31
case study of the Environment issues Assignment
Added on 2021-05-31
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1A case study of the Environment issues at Mt Morgan site in central QueenslandIntroductionMining is a process of extracting valuable geological materials and minerals from the earth. Mining also includes extraction of non- renewable sources of energy such as petroleum, coal, and natural gases. The commonly mined valuable rock deposits are gold, diamond, copper, and limestone and to the countries where these natural sources are valuable, mining is an important source of income. Mining has been a human activity for many centuries although mostof the mining activities create adverse impacts on the environment (Afum and Opoku, 2018). Hence, many nations where mining is practiced have passed environmental regulations to minimize these impacts. Mt. Morgan site is a historical gold, silver, and copper mine located approximately 32 km from Rock Hampton in Queensland Australia. It was closed after 100 yearsof mining activities due to environmental issues. Being the largest mining site in the 19th century, the project left a many effects on the site itself and Dee River. Some of the impacts left behind by the mine are tailings dump mining and Acid Rock Drainage into Dee River (Lambkin, 2011). During the early years of operation in the early 1990s, there were no environmental regulations, or they were minimal and the mining activities were at the peak during this period (Dold, 2014).A total of approximately 686,000 tons of minerals were mined from Mt Morgan site using open-cut and underground processes. The site remained an abandoned mining site until in January 2000 when the Department of Mining and Energy came up with a 10 year plan of
2rehabilitating the site (Singhal, 2009). The department also proposed a 3 years program to study the sources which were mostly contaminated, examine the water movements of River Dee and how the river was affected by the mining activities. As part of this learning program, an agreement was made between the government and the holder of leases in the country which is Norton Gold Fields Ltd in 2003. The agreement prohibits those who lease the site from dumping tailings and other wastes from mineral processing into the river. The government is still seeking to establish an agreement that would see the mine operating as commercial site thus long-term improvements of the site (Lambkin, 2011).The purpose of this paper is to analyze the mining processes, environmental implications, and the rehabilitation plans of historical siteBackgroundThe location of Mount Morgan site is adjacent to River Dee. The mining activities mostlyaffected the west side of the river. According to Wels, Findlater &McCombe (2006) the climate at the site is described as seasonal with temperature ranging between 32°C and 23°C from January to July The area receives an average of annual rainfall of 740mm where long rains are experienced between November and May. The Mount Morgan gold and copper deposits are found in Calliope Block, which runs from Rockhampton to Warwick on the eastern part of Australia (Wels, Findlater and McCombe, 2006). Generally, all rocks in Australia are consideredto lack primary permeability and structure of the stone controls those with secondary permeability. The site traces its history back to 1882 where it was opened to recover gold in largequantities since it was available in the area (Lambkin, 2011). As a result of gold extraction, considerable amounts of copper and silver were also mined. The site could not survive anymore under the pressure of environmental rules as it had caused an underground fire from its systems
3and even the damage it had caused on River Dee. Therefore the giant mine site went into liquidation in 1927 and it was later closed permanently in 1990 (Choudhary &Sheoran, 2012).1)Environmental issues of the sitePollution is an issue that has raised a lot of concern in the recent past. Mining activities impact the environment negatively and causes harm to the people who live near the mining sites(Lindbeck &Clark, 2010). Mining pollutes water, destroys aquatic life, and also destroys soil anddue to this, governments of various nations have imposed regulations to ensure that mining does not affect the environment and lives. The following are some of the ways Mount Morgan site contributed to pollution.i.Dee river color changeDue to the Acid drained into the river from Mount Morgan sites, the river has been changing its colors from, green, blue, or brown over the years. Scientists believe that presence of copper in the river is the cause of the blue-green color. Water changes its color due to many reasons, for example, the presence of blue color in River Dee occurs when the water has a pH of between 4.5 and 5.5. Water in River Dee changes its color when water from the old mine sites mixes with quality water from the downstream catchment area(Korre, Gay & Durucan, 2007). Since water from these two sources has different pH levels, water changes from one green, brown, to blue-green. The effect of minerals such as Zinc, aluminum, sulphur and other harmful chemical substances is that they destroyed aquatic life and destroyed the soil. Additionally, these chemicals made the water in the river unfit for human consumption (Singhal, 2009).ii.Acid Mineral Drainage (AMD)
4Acid Mineral Drainage is formed when sulphide minerals mix with the air naturally and it exists in form of sulphuric acid. AMD is happening in the old mines in Mount Morgan site up to date and is the primary cause of the presence of AMD in the water catchments in River Dee (Dold, 2014). iii.Open-cut overflowsIn 2013, overtopping of the spillway of the open-cut pit was experienced in Mount Morgan for the first time due to intense rainfall caused by ex-cyclone Oswald. The run-off extended for about 50km downstream River Dee but this did not have any major effects on the quality of the water in the river (Cheshire, Everingham &Lawrence, 2014)2)Mining sitesAt mount Morgan, the mining activities were carried out in the following two crucial systemsi.Seepage Interception System (SIS)Most of the seepage units in Mount Morgan site were collected from Mundic Creek area. For a long time, acid seeps have been discharging from various mine wastes. Seepage interception Systems were used to pump back acid drainages back to the pit. The SIS system consisted of 8 sumps normally used to receive groundwater and seepage acid (Choudhary and Sheoran, 2012). To ensure the effectiveness of the system, a model that allowed water to flow in the underground was developed (Korre, Gay & Durucan, 2007). This model ensured that open pits and sandstone gully carried the largest amount of seepage since they were flooded, while overburden and waste rock carried the other remaining amount of seepage. The estimated drainage from Mount Morgan passing through the SIS system into River Dee was estimated to
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