Overview of environmental impacts of mining operations to the surrounding communities with Ignatius Kamwanje – Mining & Trade Review

201709 Malawi Mining & Trade Review Ignatius Kamwanje

MINING & SOCIAL ISSUES with Ignatius Kamwanje

An Overview of Environmental Impacts of Mining Operations to the Surrounding Communities

Mining operations are perceived to have more overall negative impacts to the communities than the positive ones. In the long run it is the communities that are left  with nothing but sinkholes, displaced families, polluted environment, erosion of culture, social obligation and economic status as time passes, just to mention but a few.

In particular, these impacts are documented in the Environmental and Social Impact Assessment in line with government legislation as a requirement before any mining operation takes off and is commissioned. It is also envisaged that the government spearheads the signing of development Agreements with the mining company on behalf of the communities where mining operation shall take place.

It is a requirement by mining companies in most countries to follow strict environmental, bio-remediation measures and rehabilitation codes in order to minimize environmental and human health impact. These codes and regulations require the common steps of environmental impact assessments, development of environmental management plans, mine closure strategies, planning and environmental monitoring plans or mechanisms. All these assignments are a requisite before mining, during operation and after mine closure. It is envisaged that of particular interest, most governments in developing countries, neglect these regulations through irregular monitoring and enforcement procedures. Mining operations usually create a negative environmental impact hence, most of the countries have passed regulations to decrease the impact together with safety measures that do not prolong environmental pollution from released toxic chemicals even if after the mines are abandoned or closed.

Environmental impacts should ideally be identified and mitigated according to the phase in the mining life cycle. This is a more practical way of dealing with environmental impacts since the scale of impact differs according to stage (e.g. impacts made during exploration are much less than those made in the operational phase). In addition, the environmental monitoring and management varies with each stage of the mining life cycle.

Environmental Impacts during Mineral Exploration Stage

The first stage on management of environmental impacts of mining comes with exploration for a new deposit. Exploration activity usually impacts the least on the environment in comparison to other stages of mining. However, in the past, prospecting and exploration was the domain of non-professional prospectors, who because of lack of knowledge of the market and  requirements of the processing industry, coupled with the absence of professional exploration skills seldom conducted formal investigations or evaluations prior to opening mines. This has led to many ugly scars/sinkholes on the landscape around the world, as full scale mining commenced without any knowledge of the underlying geology, mining methods, pit optimization, grade control, tailings facilities and in these circumstances, mining was  often unsuccessful.

Successful mines provide sufficient information to make an informed decision as to whether or not to proceed to the next stage taking the risks of a negative outcome into account. At each step of this sequence, the environmental impacts are taken into account, and the minimum possible footprint is disturbed. From an environmental point of view this approach has the benefit that environmental disturbances are minimized considering the possibility of a negative outcome. Thus if an exploration project is abandoned after drilling, the environmental impact is that the order of magnitude are lower.

The field evaluation stage of exploration has minimal impact on the environment and impact is caused mainly by the exploration team’s vehicles when they clear existing flora for pathways and drill pads. Should the team choose to establish exploration camps close to the site then further environmental impacts will be caused by fires, sanitation and domestic waste disposal. This also has a minimal impact.

At the detailed mapping stage environmental impacts may start to intensify, particularly if it is necessary to mechanically clean mapping traverses. This may result in removal of vegetation and soil. In other mining types, e.g. quarrying, it is not often necessary to clear paths for mapping as fairly large solid outcrops of stone are often the exploration target and these have minimal cover if at all. Minerals extracted at this stage do not have significant impact, and the extraction sites can be concealed by replacing topsoil, or backfilling. If after detailed mapping is completed it is decided not to pursue the project further, it is relatively easy to replace the removed soil and seed with appropriate vegetation.

From the drilling stage the environmental impacts begin to become more significant, but can still be limited. The most severe environmental and social impact is land clearance caused by road construction for easier access for vehicles and air compressors resulting in damage to natural resource base, possible damage to sites of archaeological, religious or historical importance and health and safety risks to community members, livestock and wildlife.

At the bulk sampling stage the impacts are not considerably more than during the drilling phase, as a relatively small area is disturbed to extract the one or two blocks required. The impacts of bulk sampling are however limited by the relatively small area disturbed. Should a decision be made to proceed from bulk sampling to test mining, the environmental impacts are not significantly different from full scale mining, with the exception that at this stage no permanent infrastructure such as offices, workshops and other houses would be constructed.

Impacts on the natural resource base during the exploration phase may include impacts on soil, agricultural land, forest or woodland resources and surface and groundwater resources. Impacts on soil may result from vehicle traffic, drilling and materials storage resulting in soil erosion; impacts on soil structure (mainly compaction) and soil chemistry (as a result of petrochemical spills). Impacts on agricultural land may result in short term destruction of crops or grazing land or long term impacts due to disturbance of soil or vegetation which may affect long term agricultural viability The quality and quantity of surface or groundwater resources may be impacted by poor storage of chemicals and fuels resulting in spillage; inappropriate waste disposal practices; stream damming or diversion; land clearance in the upstream catchment and soil erosion.

Impacts on biodiversity may include loss of habitat, fatalities resulting from direct contact with exploration equipment and supplies (vehicles, bulldozers, chemicals, waste); Damage to or impacts on access to sites archaeological, religious or historical significance can be incredibly emotive and inflict major damage on the relationship with the local community. Exploration poses a risk to the health and safety of community members, livestock and wildlife through contact with machinery and vehicles; excavations and contact with chemicals and fuels.

Environmental Impacts during the Development Stage

Development is the preparation of the facilities, equipment, and infrastructure required for extraction of the valuable mineral material, and the phase includes land acquisition, equipment selection and specification, infrastructure and surface facilities design and construction, environmental planning and permitting, and initial mine planning. During this phase of many mining projects, there may also be a need for involuntary relocation of communities located in proximity to the proposed mining area. This can be a fatal flaw of a project and should be facilitated by qualified and experienced consultants. Given the nature of the mining methods employed, it is possible to mine safely much closer to human settlements than with most other surface mines and quarries.

In equipment selection, it is necessary to consider the sources of power to be used for the equipment.  If the project is situated at high altitude, consideration must also be given to the fact that the engines of diesel powered earthmoving equipment may require modification in order to operate efficiently. Roads should be designed in such a way as to avoid soil erosion and to cause as little disturbance to flora as possible. Maintenance workshops should be designed to avoid contamination of soil and water by spilled fuel and lubricants.

The construction phase is associated with a number of environmental impacts resulting from excessive site clearance, poor waste management, poor site water management and socio-economic impacts. Impacts that may be caused by excessive site clearance during the construction phase, in addition to those mentioned in the exploration phase, are excessive dust problems, increased soil erosion and increased noise due to vehicle traffic and the use of explosives. The buffer (mainly vegetation), limited noise and dust to local communities may also be removed.

Poor waste management practices at this stage are particularly extensive due to a lack of established waste disposal facilities, ignorance of how to dispose of certain waste streams and failure to train the construction workforce in appropriate waste disposal. The types of waste that need to be disposed of at this point are construction waste, packaging   material, oils and greases from construction fleet, tyres and domestic refuse (should there be camps around the site).

The main environmental impact resulting from poor site water management is associated with storm water management; especially in high intensity rainfall areas. Poor site water management can undermine or destroy structures, limit or even suspend site access, cause major soil erosion and lead to widespread contamination if flood events wash away poorly contained hydrocarbons or chemicals.

Impacts of construction on the social environment have to also be taken into consideration, especially if there is a pre-existing community near the proposed mining project. These impacts include public health risk caused by increased vehicle traffic (dust, hydrocarbon spillage, greenhouse gas emissions) and access to unsecured infrastructure under construction; nuisance factors such as noise, dust and vibration; adverse impact on traditional lifestyle of local communities for example alcohol abuse, prostitution, introduction of a cash economy, in-migration and breakdown of traditional tribal culture.

Environmental Impacts during the Extraction Phase

The major impact of mining on the environment is the aesthetic visual impact upon the landscape. Any mining activity which disturbs the surface of the earth will have a visual impact for its duration. Environmental impacts not associated with infrastructure include impacts to groundwater, surface water and communities. Groundwater inflow in surface mining operations can flood the lower sections of the pit – provided that the pit has surpassed the depth to the water table. High pore pressures in side walls can trigger collapse, leading to catastrophic events.

Disturbance of the earth’s surface by any form of mining will result in complete removal of existing vegetation and ecosystems within the disturbed area, and dimension stone mining is no exception. The impacts are significant, but localized to the disturbed area, and the overall extent of the impact is determined by the concentration of mining and the sensitivity of the disturbed ecosystems. A proper environmental impact assessment (EIA) process will however identify areas where mining would cause irreparable damage, and mining should be excluded from such areas.

***

This piece was initially published in Malawi’s Mining & Trade Review Issue Number 58 (February 2018).

The full edition is available for download here. This monthly publication is edited by Marcel Chimwala.

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