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Land rehabilitation as a part of environmental remediation is the process of returning the land in a given area to some degree of its former state, after some process (industry, natural disasters, etc.) has resulted in its damage. Many projects and developments will result in the land becoming degraded, for example mining, farming and forestry. It is crucial that governments and businesses act proactively by working on improvement, lay out rehabilitation standards and ensure that decisions on mediation should be based around value judgment for higher sustainability in the future. [1]
In some jurisdictions, including parts of the United States, [2] the term "reclamation" can refer to land rehabilitation, as in returning disturbed lands to an improved state, instead of the land fill of water bodies. In Alberta, Canada, for example, reclamation is defined by the provincial government as "The process of reconverting disturbed land to its former or other productive uses." [3]
Modern mine rehabilitation aims to minimize and mitigate the environmental effects of modern mining, which may in the case of open pit mining involve movement of significant volumes of rock. Rehabilitation management is an ongoing process, often resulting in open pit mines being backfilled.
After mining finishes, the mine area must undergo rehabilitation.
For underground mines, rehabilitation is not always a significant problem or cost. This is because of the higher grade of the ore and lower volumes of waste rock and tailings. In some situations, stopes are backfilled with concrete slurry using waste, so that minimal waste is left at surface.
The removal of plant and infrastructure is not always part of a rehabilitation programme, as many old mine plants have cultural heritage and cultural value. Often in gold mines, rehabilitation is performed by scavenger operations which treat the soil within the plant area for spilled gold using modified placer mining gravity collection plants.
Also possible is that the section of the mine that is below ground, is kept and used to provide heating, water and/or methane. Heat extraction can be done using heat exchangers, that convey the heat to a nearby city (hence making it be used for district heating purposes. [4] Water can be harvested from the mine as well (mines are often filled with water once the mine has been shut down and the pumps no longer operate). Methane is also often present in the mine shafts, in small quantities (often around 0.1%). This can still be recovered though with specialised systems. [5] [6] [7] An added advantage of recovering the methane finally is that the methane does not come into the atmosphere, and so does not contribute to global warming. As research methods continue to expand the focus for future studies should be directed at the correlation that can be observed between biodiversity, mine ecological restoration and carbon sequestration. [8]
Depending on the country, mining companies are regulated by federal and state bodies to rehabilitate the affected land and to restore biodiversity offset areas around the mines. [9] [10]
Mine rehabilitation, a legal obligation for mining companies in Australia for which they are required to pay bonds, could be a source of considerable employment generation and economic investment in regional areas, if governments were willing to enforce the laws covering the process. [11] [12] [13] [14]
Before mining activities begin, a rehabilitation security bond must be provided. [15] The Australian mine rehabilitation bonds totals $9.49 billion, with the state of NSW bond totaling $2.68bn in 2019. The size of mining security bonds has been questioned by NSW's Auditor General [16] as being insufficient to cover the complete costs associated with mine rehabilitation activities.
In addition to operational mine rehabilitation activities, often termed 'progressive rehabilitation', abandoned mines are also restored. The financing for restoring abandoned mines is drawn from operating mines and public sources. The cost of reclaiming the abandoned mines in the US is estimated at $9.6bn.
Environmental geology, like hydrogeology, is an applied science concerned with the practical application of the principles of geology in the solving of environmental problems created by man. It is a multidisciplinary field that is closely related to engineering geology and, to a lesser extent, to environmental geography. Each of these fields involves the study of the interaction of humans with the geologic environment, including the biosphere, the lithosphere, the hydrosphere, and to some extent the atmosphere. In other words, environmental geology is the application of geological information to solve conflicts, minimizing possible adverse environmental degradation, or maximizing possible advantageous conditions resulting from the use of natural and modified environment. With an increasing world population and industrialization, the natural environment and resources are under high strain which puts them at the forefront of world issues. Environmental geology is on the rise with these issues as solutions are found by utilizing it.
Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock or minerals from the earth.
A gravel pit is an open-pit mine for the extraction of gravel.
Environmental remediation is the cleanup of hazardous substances dealing with the removal, treatment and containment of pollution or contaminants from environmental media such as soil, groundwater, sediment. Remediation may be required by regulations before development of land revitalization projects. Developers who agree to voluntary cleanup may be offered incentives under state or municipal programs like New York State's Brownfield Cleanup Program. If remediation is done by removal the waste materials are simply transported off-site for disposal at another location. The waste material can also be contained by physical barriers like slurry walls. The use of slurry walls is well-established in the construction industry. The application of (low) pressure grouting, used to mitigate soil liquefaction risks in San Francisco and other earthquake zones, has achieved mixed results in field tests to create barriers, and site-specific results depend upon many variable conditions that can greatly impact outcomes.
In mining, tailings or tails are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different from overburden, which is the waste rock or other material that overlies an ore or mineral body and is displaced during mining without being processed.
Mine reclamation is the process of modifying land that has been mined to restore it to an ecologically functional or economically usable state. Although the process of mine reclamation occurs once mining is complete, the planning of mine reclamation activities may occur prior to a mine being permitted or started. Mine reclamation creates useful landscapes that meet a variety of goals, ranging from the restoration of productive ecosystems to the creation of industrial and municipal resources. In the United States, mine reclamation is a regular part of modern mining practices. Modern mine reclamation reduces the environmental effects of mining.
Environmental technology (envirotech) is the use of engineering and technological approaches to understand and address issues that affect the environment with the aim of fostering environmental improvement. It involves the application of science and technology in the process of addressing environmental challenges through environmental conservation and the mitigation of human impact to the environment.
Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels.
Biodegradable waste includes any organic matter in waste which can be broken down into carbon dioxide, water, methane, compost, humus, and simple organic molecules by micro-organisms and other living things by composting, aerobic digestion, anaerobic digestion or similar processes. It mainly includes kitchen waste, ash, soil, dung and other plant matter. In waste management, it also includes some inorganic materials which can be decomposed by bacteria. Such materials include gypsum and its products such as plasterboard and other simple sulfates which can be decomposed by sulfate reducing bacteria to yield hydrogen sulfide in anaerobic land-fill conditions.
Soil salinity control refers to controlling the process and progress of soil salinity to prevent soil degradation by salination and reclamation of already salty (saline) soils. Soil reclamation is also known as soil improvement, rehabilitation, remediation, recuperation, or amelioration.
In-situ leaching (ISL), also called in-situ recovery (ISR) or solution mining, is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit, in situ. In-situ leach works by artificially dissolving minerals occurring naturally in the solid state.
The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal burning produces hundreds of millions of tons of solid waste products annually, including fly ash, bottom ash, and flue-gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals. Coal is the largest contributor to the human-made increase of carbon dioxide in Earth's atmosphere.
Environmental impact of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change.
Land restoration, which may include renaturalisation or rewilding, is the process of restoring land to a different or previous state with an intended purpose. That purpose can be a variety of things such as what follows: being safe for humans, plants, and animals; stabilizing ecological communities; cleaning up pollution; creating novel ecosystems; or restoring the land to a historical condition, for example how indigenous people managed the land. Ecological destruction or degradation, to which land restoration serves as an antidote, is usually the consequence of human influence's intended or unintended consequences. This can include pollution, deforestation, salination, or species endangerment, among many more. Land restoration is not the same as land reclamation, where existing ecosystems are altered or destroyed to give way for cultivation or construction. Land restoration can enhance the supply of valuable ecosystem services that benefit people.
Coal mining in Brazil is an important part of the country's energy economy as its largest source of non-renewable energy. Brazil is the tenth largest energy consumer in the world and the third largest in the Western Hemisphere. Coal accounts for approximately 5.8 percent of the country's total primary energy supply. It is the country's largest source of non-renewable energy, followed by nuclear energy, petroleum, and natural gas. Brazil produces about 6 million tons of coal per year, and total coal reserves are estimated at approximately 32.3 billion tons. It is also important in reducing reliance on imported oil and gas. Brazil's coal-mining region is located in the southern part of the country, and the reserves are distributed among the states of Paraná, Santa Catarina, and Rio Grande do Sul. The southernmost state of Rio Grande do Sul has the majority of the coal reserves, but Santa Catarina is the largest producer of coal. The total Brazilian coal production in 2007 was 12,144,564 short tons, with the state of Santa Catarina producing 7,228,895 of those. The coal mining industry is of tremendous importance to these regions, given the rapid expansion of Brazil's national economy. It is also important in reducing reliance on hydropower from other regions.
Mount Polley mine is a Canadian gold and copper mine located in British Columbia near the towns of Williams Lake and Likely. It consists of two open-pit sites with an underground mining component and is owned and operated by the Mount Polley Mining Corporation, a wholly owned subsidiary of Imperial Metals. In 2013, the mine produced an output of 38,501,165 pounds (17,463,835 kg) of copper, 45,823 ounces of gold, and 123,999 of silver. The mill commenced operations in 1997 and was closed and placed on care and maintenance in 2019. The company owns 20,113 hectares (201.13 km2) of property near Quesnel Lake and Polley Lake where it has mining leases and operations on 2,007 hectares (20.07 km2) and mineral claims on 18,106 hectares (181.06 km2). Mineral concentrate is delivered by truck to the Port of Vancouver.
Water in Arkansas is an important issue encompassing the conservation, protection, management, distribution and use of the water resource in the state. Arkansas contains a mixture of groundwater and surface water, with a variety of state and federal agencies responsible for the regulation of the water resource. In accordance with agency rules, state, and federal law, the state's water treatment facilities utilize engineering, chemistry, science and technology to treat raw water from the environment to potable water standards and distribute it through water mains to homes, farms, business and industrial customers. Following use, wastewater is collected in collection and conveyance systems, decentralized sewer systems or septic tanks and treated in accordance with regulations at publicly owned treatment works (POTWs) before being discharged to the environment.
According to a survey completed by the Colorado Geological Survey between 1991 and 1999, the number of abandoned mines in Colorado is 18,382. The Arkansas Headwaters, Las Animas River, Rio Grande Headwaters, Alamosa, and Uncompahgre were the priority watersheds studied in this survey. In the survey, analysis was completed with Environmental Degradation Measures ranging from none to extreme. Results showed 26 abandoned mines with extreme degradation and mineral hazards, 219 with significant degradation, and 672 potentially significant hazards.
Legacy pollution or legacy pollutants are persistent materials in the environment that were created through a polluting industry or process that have polluting effects after the process has finished. Frequently these include persistent organic pollutants, heavy metals or other chemicals residual in the environment long after the industrial or extraction processes that produced them. Often these are chemicals produced by industry and polluted before there was widespread awareness of the toxic effects of the pollutants, and subsequently regulated or banned. Notable legacy pollutants include mercury, PCBs, Dioxins and other chemicals that are widespread health and environmental effects. Sites for legacy pollutants include mining sites, industrial parks, waterways contaminated by industry, and other dump sites.