Mines are human-made structures, and this basic fact already tells us a lot about the nature of mining as an industry. While the mineral deposits that make mining profitable are already present underground, mining companies still need to prepare the infrastructure necessary to extract and process these resources.
As a mine operates, its resources will eventually deplete to the point where further mining becomes unprofitable. The mine then needs to be closed in such a way that it can still provide something of value to the surrounding community. As mines can become environmentally disruptive, procedures must be in place to facilitate the ecological restoration of the site.
Evidently, the mining life cycle exists, and the nature of operations changes drastically as the mine matures. Hence, the creation of mine involves extensive planning, making it essential to adopt a project management workflow that considers the mining life cycle. Understanding the mining life cycle is critical to optimizing mining operations.
Naturally, the first stage of the life of a mine involves searching for geological sites that may potentially contain valuable mineral deposits. This phase is called prospecting, and it is complicated by the fact that you can find many deposits underground.
To accurately assess the potential of a site, geologists and mining engineers work together by performing analyses and inspection methods to determine the presence and approximate extent of the resource. Prospecting usually lasts for 1-2 years and may cost USD 10 million, but it is an essential step despite its cost, as this gives the chance to move to another site if there is not enough evidence for profitability.
Once the surveyors establish the presence of the mineral deposit, the next phase of mine development starts. This exploration phase is where they conduct a feasibility study to characterize the quality and range of the underground resource further.
In this phase, exploratory drilling is usually performed to describe the properties of the mineral deposit. The exploration’s goal is to determine the bounds of the resource, the estimated tonnage that can be extracted, and the approximate financial value of the deposit. Exploration can take up to 5 years and cost up to USD 15 million.
Once the feasibility of the resource is proven, the site needs to be developed to facilitate the easier extraction of the valuable product. Development includes acquiring the rights to operate the land as well as the procurement of other necessary permits as required by law.
Some form of environmental impact statement also needs to be submitted to the authorities to reassure them that there are plans in place to limit the negative environmental impact of mining operations.
Development also includes the excavation of the overburden, which refers to the non-valuable rock covering the ore deposit, or the creation of underground tunnels to gain access to the deposit. This phase has a similar time frame as exploration but is around ten times more expensive.
Large-scale mining, also known as exploitation, can proceed after the mine has been adequately prepared. This stage is the execution phase of the entire project and is when most of the recoverable minerals are extracted.
Extensive use of equipment and workforce are the distinctive characteristics of the exploitation phase, and expansion tasks are frequent as more of the deposit is utilized. Exploitation can run for decades, depending on the mining speed and the size of the resource.
Once the mine has been exhausted, measures are taken to prepare for mine closure. These measures are collectively classified under the reclamation phase. Equipment and other capital assets are removed from the site, and any generated wastes are secured, treated, and disposed of properly to prevent environmental contamination.
The location is stabilized to ensure the structural integrity of the site, and attempts are made to restore the natural flora and fauna that existed before mining. Finally, regular monitoring is done for a few years to check the progress of reclamation and restoration to normal conditions.