Implications Of Exploration Economic Geology At Mt. Morgan Site In Queensland Australia

Discuss About The Implications Exploration Economic Geology.

Mining 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 most of the mining activities create adverse impacts on the environment (Afum and Opoku, 2018). Healthcare, 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 years of 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 rehabilitating 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 site

Seepage Interception System (SIS)

The location of Mount Morgan site is adjacent to River Dee. The mining activities mostly affected 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 considered to 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 large quantities since it was available in the area (Lambkin, 2011). As a result of gold extraction, considerable accounting 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 and 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).

• Environmental issues of the site

Pollution 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 and due 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.

1. Dee river color change

Due 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).

1. Acid Mineral Drainage (AMD)

Groundwater System

Acid 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).

• Open-cut overflows

In 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)

• Mining sites

At mount Morgan, the mining activities were carried out in the following two crucial systems

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 be 300 meter cubic per day. The Mundic tailings were the only ones placed between the historical Mundic and Linda creed while the rest tailings were placed into the dams (Singhal, 2009).

The groundwater system at Mount Morgan site was designed to follow a natural topography from the open cut pits towards River Dee Valley. The system was subdivided into four basic hydrostratigraphic units which are basement rock, fractured bedrock, weathered bedrock, and waste rock and tailings. The presence of colluvial deposits at fracturing of rocks at the historical Mundic and Linda creek which are ancient drainages in the area highly favored the natural flow of groundwater from the source to the west of River Dee (Afum & Opoku, 2018). The system was recharged using the seepage that runs through the system from the sandstone gully and pits. Waste rocks also provided the seepage that revived the system (Holland, Duivenvoorden & Kinnear, 2014).

The groundwater in the mine consisted high levels of AMD from the open fits and sandstone gully and the most common ions present were aluminum, sulphate and magnesium (Buzzi et al., 2013). The percentage of acidification in the groundwater in the site, therefore, varied depending on the strength and the type of the ion passing through the system. For example, the drainage at Linda Creek was generally acidic due to the presence of aluminum chemicals from the open cut pit. As a result, the quality of underground water entering River Dee from this area was very poor. In other words, all the mining units in the Mount Morgan sites produced seeping which consisted of the harmful acid drainage minerals (Cheshire, Everingham & Lawrence, 2014)

Since the mine was closed down in 1992 following environmental issues, nothing much has been going on there and the site has been a tourist attraction in the region. However, the government announced its plan to rehabilitate the site in 2011 but under strict environmental regulations.

• Redefining Mt. Morgan site

In the history of Queensway Mount Morgan site is a significant heritage and it was stored in the Heritage Act in 1992. Although the mining activities of the site had severe effects on River Dee and the surrounding area, the government has put proposals in place to make the site operational again (Lambkin, 2011).  As part of the government programs and the Norton leasing company, there have been activities going on in the site with the initial purpose of discovering gold and copper from the site. So far, approximately 10 million tons recovered from the historical site mainly from the open cut pit and they are expected to last for another nine to ten years. The developments experienced from the site are facilitated by test work using mineral processing flow sheets. Following the ongoing mining process in the area, more mineral processing units are being set on the site (Wels, Findlater and McCombe, 2006).

All the mining activities in the area are overseen by Carbine project operator which operates under the agreement between the government and Norton. Escalators extract all the mineral tailings and then transported to ROM stockpile by trucks. The slags which are found on Red Oxide rocks are compact and hard, so they require occasional blasting to break (Singhal, 2009).  The roads leading to the mine were upgraded and haul roads constructed to ensure smooth and safe movement of trucks in and out of the site. According to the Environmental Authority, all the areas that Carbine has been extracting minerals for the last 10 years require rehabilitation as stated in the agreement between the government and the leasing company Norton. The agreement says that all materials contaminated with ARD seepage should be removed from the area (Taube, 2005).

• Current land use

Despite the government efforts to rehabilitate the site, only 15% of the total land is under use by Carbine mining project. Due to this reason, the land has continued to be a source of AMD since most of the wastes from the open cut dump sites continue to flow into River Dee and other water catchment areas found near the site. The government has the responsibility to manage the unutilized land and at the same safeguard the heritage of the site as it serves as tourist attraction site (Abzalov and Newman, 2017). Most of the property in the area has remained un-rehabilitated and people visit the area occasionally to learn and interact with nature. Carbine in partnership with local commercial operators serves the visitors with information concerning the history of the mine and the mineral extraction process. These tours to the historical site of Mount Morgan are expected to expand in future. Currently, there are plans underway by the government to repair and maintain the buildings in the place with high-value heritage. Additionally, it is expected that Carbine will continue using the existing resources at the site in the mine time (Parbhakar, 2016).

The ongoing mining and construction processes in the Mount Morgan site are not without effects on the local people who live near the site. People are being affected by noise from vehicle movement and mining activities, as well as dust in the area. However, these impacts are regulated under Environmental Act, Queensway Act, and Mineral Resources Act. Under these Acts, Carbine is required to meet the requirements laid down in the Act (Parbhakar, 2016). Simply, the tailings mining should not produce dust and in case it happens, dust suppressions should be used if the limit is exceeded. Noise from blasting Red Oxide rocks is also a disturbance to the locals and so, Carbine is required to use only open face blasting to minimize the noise. In future, the mining company is expected to invent other methods of breaking the tailings which are environmental-friendly. Before the site was closed in 1990, smelting was used which produced irritating odor but under the new Acts regulating the operations of the mining company, smelting is not allowed (Taube, 2005).

• Environmental implications of the site

The Acid Drainage Minerals and seepage has been affecting the environment of Queensway for so many years. Initially, mining operations at the site were not regulated by the government and this led to careless extraction processes which are continuing to affect future generations of people in the area. One of the severe damages caused by the mining activities is the acid drainage into River Dee. Although the government has been trying to purify the water in the river, there is nothing much which has been achieved so far because the acid has caused the pH levels to rise (Lindbeck and Clark, 2010). Acidic water is harmful to human and aquatic life. The acid kills fish found in the river or they are damaged. Acidic water flowing into River Dee has completely disrupted the animal system and food chain. For example when it floods and the sites, water from the open mines flows into the river. The water from the mine is acidic and it causes diseases to fish found in the river. Consumption of the fish by human beings is also harmful to their health. Additionally, the presence of acid in the water makes it unfit for people to use. Water is life but not all water is suitable for use (Abzalov and Newman, 2017).

The government must ensure that it prevent further damage to the environment from the site. In the effort to achieve this, the government and the local authorities in Queensway are trying to reduce the water levels in the open pit by evaporation. By doing this, the government is hoping to completely dry the acidic water so that it does not flow into the river anymore (Cheshire, Everingham &Lawrence, 2014). However, the problem with this process is that evaporation is not long-term solutions to the problem because when it rains the pits are filled with water and it ends up finding its way into the river. Evaporation cannot work well to prevent acidic water drainage into the waterways. As it is widely known, when water evaporates, it condenses and falls in another area as rainfall (Afum & Opoku, 2018). Evaporated water from Mount Morgan consists of harmful acids and when it rains in another place, it also harms the people and the animals found in that area. The most appropriate thing to do by the government is to develop a program of treating the water from the open pits so that in case if finds its water into the river, there will be no damage. Water treatment makes it free from chemicals and acid and no harm will be caused (Dold, 2014).

Conclusion

Mount Morgan is a legacy site that is generating millions of dollars for the government and supporting many people in the country. However, the adverse effects caused by the mine cannot be ignored because they cost lives of people and animals (Holland & Kinnear 2014). For so many decades, the government has been trying to come up with programs of eradicating the acid chemicals found in the site but unfortunately, pollution remains a burden in the area and there is a long way to go to completely clean River Dee. There is a lot that needs to be done towards achieving the acid-free environment that will support human life and animal existence. People are suffering today due to pollution. It is the responsibility of the government to protect the lives of its people by ensuring that they have access to clean water. Additionally, the land can also be used for other purposes like farming where people can do farming to improve their standards of living. From the study, it is evident that mining have destroyed environment in Australia and it is unfortunate that no action was being taken for miners who contributed to environmental pollution before. People engaged in mining freely without caring for the environment because they knew that no action would be taken against the. Pollution is a menace that affects the future generations as it is seen that River Dee is still affected by mining activities that took place some 100 years ago. The purpose of this study was to demonstrate how mining can impact the environment negatively and to show what the government can do eliminate these impacts.

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