How are mines built? And what happens when they are depleted? The lifecycle of a mine includes five main stages.
One of the key processes that investors interested in the mining industry should understand is how mines are built. Each step may take years and involves different levels of investment risk.
The early stages of mine building are particularly risky. Junior miners are still a long way from production, and will face many obstacles before they get there. However, even these mining companies can be a good investment in the mining sector for those who do their due diligence and ask the right questions.
With that in mind, here’s an overview of the lifecycle of a mine from birth to death. In total, there are five main stages: prospecting and exploration of resources, assessment and approval, construction, production, closure and rehabilitation.
1. Lifecycle of a mine: Prospecting and exploration
Prospecting and exploration are precursors to mining and development and often happen at the same time. Historically, prospectors would explore a region on foot with a pick and a shovel as mining methods looking for metals, but today there are more high-tech methods that mining companies can use when searching a region for mineral deposits. Prospecting can take anywhere from one to two years.
During mineral exploration, experts like geologists use additional techniques to determine the possible size and value of the mineral deposit discovered during prospecting. Exploration involves sampling, mapping, diamond drilling and other work. This stage is estimated to last between three and 14 years depending on the project. It generally involves data collection for environmental impact studies and the completion of a mineral resource estimate.
2. Lifecycle of a mine: Assessment and approval
Once prospecting and exploration are finished, deposit details and environmental and socioeconomic information collected during exploration are used to plan and design a mine.
Companies only build mines if they are sure they have found a deposit valuable enough to justify the money they will have to spend to bring it into production. Costs they will need to cover include mine design and construction and costs of operations, as well as mine closure and reclamation expenses.
To discover whether the deposit they have found is economic, companies generally complete several technical studies. These studies include preliminary economic assessments, along with prefeasibility and a feasibility studies. All three analyze and assess the same geological, engineering and economic factors, but the level of detail and precision is significantly different.
In general, it takes two to three years for mining companies to amass this data.
During this time, companies will also usually look to secure various permits, a process that can take one to three years or even longer. They also tend to spend time raising money to support these expensive and high-risk steps.
3. Lifecycle of a mine: Construction
All of the preliminary and technical reports completed during the first two stages serve as tools that provide companies with the information they need to make intelligent and strategic decisions regarding the development of a project. Once they have all of this information, they will decide if they will go ahead with the mine construction phase.
The construction process occurs after research, permitting and approvals have all been completed. Building a mine site can involve setting up roads, mining processing facilities, environmental management systems, employee housing and other facilities.
4. Lifecycle of a mine: Production
Once the construction phase is finished, the mine begins to produce. Production usually last from 10 to 30 years, but in some cases can continue for even longer than that. Mine production involves the extraction of ore, separation of minerals, disposal of waste and shipment of product.
The two most common methods of mining are surface and underground mining. Companies determine what type of extraction to do based on the characteristics of their mineral deposit and the limits imposed by safety and technology, as well as environmental and economical concerns.
Mine production involves three main stages:
- Processing: At this point of the mining process, ore is treated to separate valuable minerals from waste rock.
- Recovering minerals: Also called mineral extraction. This is the process of extracting ore from rock using different tools and machinery.
- Smelting: This process involves melting concentrate to extract metals like zinc, copper or precious metals from ore.
5. Lifecycle of a mine: Project closure and rehabilitation
Once a mine site has been exhausted, the process of closure occurs; this stage involves dismantling all facilities on the property. Reclamation then begins, allowing the land to return to its original state. This last phase can take anywhere from one to 10 years.
Mining of resources involves the temporary use of land, and the goal of reclamation is for areas affected by mining activity to once again host self-sustaining ecosystems that provide a healthy environment for fish, wildlife and humans.
This is an updated version of an article first published by the Investing News Network in 2013.
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Securities Disclosure: I, Priscila Barrera, hold no direct investment interest in any company mentioned in this article.