The Perfect Mine, From the Environmental Perspective

The complaints that are heard about mining operations are of three types: damage to the environment and biodiversity; lack of respect for neighboring communities; and that the taxes miners pay are very low, compared to the profits they obtain.

I have not heard this argument so frequently about agriculture, which is also carried out in rural areas, far from cities. Regarding that sector, few people talk about environmental damage, even less about respect for neighboring communities, and no one complains about the taxes they pay, or the magnitude of their profits. The only complaint I have heard is related to labor practices. Why is that?

Why is it that these complaints focus more on mining, if the products obtained in both industries are essential for life? Food and minerals are both essential for life. Mineral-derived products, such as fertilizers, materials for construction, and for the manufacturing of homes, cities, vehicles, mobile phones, computers, among others, fall into this category. In both cases, there are national and international producers, some producers are more responsible than others, both can contaminate water sources and damage biodiversity, and they are also the few sources of employment in rural areas. These are industries that, although equally important for humanity, receive different treatment from government agencies, from neighboring communities, and from the media.

  In Mexico, we see that the government opposes open-pit mining operations without indicating why, although one might think that its opposition is due to the scar left on the surface. The argument has validity because at the end of the mining operation, a pit remains, which in addition to affecting the landscape can represent a danger to neighbors; therefore, it is necessary to find a remedy, which reduces these two issues to a minimum.

What would a perfect mine look like from the perspective of minimizing environmental damage? The most relevant aspects that can cause environmental damage are:

• The plan for closing the pit, to minimize the effect on the landscape. 

• The plan for managing tailings, in a way that does not represent a danger.’

• The sources of water, which may affect community users.

• The discharges of contaminated water into the environment, which should be as little and of the best quality as possible.

• Compensation for the change in land use to achieve a net positive effect on biodiversity.

Closing the pit: At the end of the mining operation, a pit remains. Of the available options, the cheapest, if surface or groundwater is available, would be to let it fill with rainwater, surface water from nearby streams, or groundwater, and turn it into a lake, which can be used for recreation or other beneficial uses; there are several examples of this around the world. The other option is to fill the pit with residual material from the mining operation, such as filtered tailings and waste rock. This option is not cheap but reduces risks and eliminates the impact on the landscape. This must be accompanied by a financial guarantee, liquid and independent of the mining company, which covers all expenses associated with the closure.  

The tailings from a mining operation are a significant waste, which can be a hazard, due to the volume it occupies and especially if it is stored with water behind a dam. The preferred option for many miners, because it reduces risks, is to stack the tailings, after passing them through a filtration plant that removes the water and leaves a residual moisture that allows it to be mechanically compacted. This avoids having to build dams; however, it requires design and engineering expertise, but eliminates the risks associated with a dam breaking, which can cause deaths and environmental damage and exposes the company to multimillion or billion-dollar lawsuits.

Water supply is key to mining operations, and is a source of potential conflict, especially in places experiencing water scarcity.  A mining operation usually has more money to build wells than neighboring communities, thus putting them at a disadvantage when competing for water. There are several options. One is to build dams to store rainwater and river water, in a volume sufficient to supply the operation. This type of infrastructure lasts beyond the life of the mine, and can be a positive legacy for the community. Another option is to extract groundwater through wells and take responsibility for the supply of drinking water to nearby communities, which are affected by the mining operation's extraction, as it lowers the groundwater level and increases pumping costs. When the operation is close to the sea, the water can be desalinated. When the operation is close to a city, the wastewater of the city could be used after treatment for the operation of the mine. 

Mining operations that choose to filter tailings can become zero-discharge operations. By extracting water from tailings, they do not have to discharge process wastewater into the environment, because they reuse it and reduce the amount of fresh water they require.

Mining operations can be seen in most cases as a temporary change in land use. The time frame can be from 10 years to 50 years,  and longer in some cases, after which the area is restored and can have another type of use.  International trends require that companies compensate for vegetation and ecosystems that have been affected, so that the net effect is positive, and which must be maintained as the mining operation progresses.

These considerations increase the capital required to build and operate the mine, and increase the time required to recover the invested capital, but eliminate the aspects that generate the most environmental impacts and, therefore, reduce risks.  These measures remove the government's excuses for not approving open-pit mines. If the mining company can add to this by developing and obtaining an impacts and benefits agreement with the neighboring communities, then it becomes a winning combination.   Who will come to Mexico to invest in mining? The most responsible and the most committed to their good reputation. Clear rules attract the most suitable investment.