Regenerated habitat for superb parrot on the abandoned Boorowa railway line

Land rehabilitation as a part of

environmental remediation Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water. Remedial action is generally subject to an array of regulatory requirements, and may al ...

is the process of returning the land in a given area to some degree of its former state, after some process (

industry Industry may refer to: Economics * Industry (economics), a generally categorized branch of economic activity * Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery * The wider industrial sector ...

natural disaster A natural disaster is "the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community". A natural disaster can cause loss of life or damage property, and typically leaves some econ ...

s, etc.) has resulted in its damage. Many

project A project is any undertaking, carried out individually or collaboratively and possibly involving research or design, that is carefully planned to achieve a particular goal. An alternative view sees a project managerially as a sequence of even ...

s and

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

s will result in the land becoming degraded, for example

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

farming Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

and

forestry Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests, woodlands, and associated resources for human and environmental benefits. Forestry is practiced in plantations and natural stands. Th ...

Mine rehabilitation

Modern mine rehabilitation aims to minimize and mitigate the environmental effects of modern mining, which may in the case of

open pit Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of minin ...

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. *

Waste dump A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste ...

s are contoured to flatten them out, to further stabilize them against

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

. * If the ore contains

sulfides Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

it is usually covered with a layer of

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

to prevent access of

rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

and

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

from the

air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

, which can

oxidize Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

the sulfides to produce

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

. *

Landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste ...

s are covered with

topsoil Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Description Topsoil is composed of mineral particles and organic matt ...

, and

vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic character ...

is planted to help consolidate the material. * Dumps are usually fenced off to prevent

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...

denuding them of vegetation. * The open pit is then surrounded with a fence, to prevent access, and it generally eventually fills up with

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...

. *

Tailings In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overlie ...

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s are left to

evaporate Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...

, then covered with waste rock, clay if need be, and

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...

, which is planted to stabilize it. For underground mines, rehabilitation is not always a significant problem or cost. This is because of the higher grade of the

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

and lower volumes of waste rock and tailings. In some situations, stopes are backfilled with

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...

slurry A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pu ...

using waste, so that minimal waste is left at surface. The removal of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

and

infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...

is not always part of a rehabilitation programme, as many old mine plants have

cultural heritage Cultural heritage is the heritage of tangible and intangible heritage assets of a group or society that is inherited from past generations. Not all heritages of past generations are "heritage"; rather, heritage is a product of selection by soci ...

and

cultural Culture () is an umbrella term which encompasses the social behavior, institutions, and Social norm, norms found in human Society, societies, as well as the knowledge, beliefs, arts, laws, Social norm, customs, capabilities, and habits of the ...

value. Often in

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

mines, rehabilitation is performed by scavenger operations which treat the soil within the plant area for spilled gold using modified

placer mining Placer mining () is the mining of stream bed (Alluvium, alluvial) deposits for minerals. This may be done by open-pit mining, open-pit (also called open-cast mining) or by various surface excavating equipment or tunneling equipment. Placer minin ...

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

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 District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating a ...

purposes. 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. 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.

Mine rehabilitation market

Depending on the country, Mining companies are regulated by federal and state bodies to rehabilitate the affected land and to restore

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

offset areas around the mines. 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. Before mining activities begin, a rehabilitation security bond must be provided. The Australian mine rehabilitation bonds totals $9.49bn, with the state of NSW bond totalling $2.68 billion in 2019. The size of mining security bonds has been questioned by NSW's Auditor General https://www.audit.nsw.gov.au/sites/default/files/pdf-downloads/01_Mining_Rehabilitation_Security_Deposits_Final_Report.pdf as being insufficient to cover the complete costs associated with mine rehabilitation activities. In addition to operational mine rehabilitation activities, often referred to as 'progressive rehabilitation', abandoned mines are also restored. The financing for restoration of abandoned mines is drawn from operating mines as well as public sources. The cost of reclaiming the abandoned mines in the US is estimated at $9.6bn.

References

{{Reflist

External links

* Rehabilitation of waterlogged and saline soils

free downloads of software and articles on land drainage.
Bio Recycle

Sydney Water BioSolidsEEMP
- a non-profit 501 (c) 3 organization dedicated to communicate the lessons of rehabilitation and restoration through media around the world. * Federal Environmental Laws that Govern U.S. Mining

* NSW Australia Mine Rehabilitation

Construction Environmental issues with soil Economic geology Landscape Land management Ecological restoration da:Naturgenopretning et:Rekultiveerimine fr:Renaturation pl:Renaturyzacja

Mine rehabilitation

Mine rehabilitation market

See also

References

External links