Open pit mining is an extraction process used to extract metallic and non-metallic minerals from the surface, forming openings that conform to the economic deposits of these minerals. This method of mining directly interfaces with the external atmosphere.
Many gold mining companies opt for this method. Open pit mining is the approach to prospecting for gold mineral ore by opening up a specific area for mining. Moreover, the expenses involved are considerably lower when compared to underground mining methods.
In principle, the stages of the open pit mining process are as follows:
- Land clearing by removing all vegetation covering the ground (clearing and grubbing) using bulldozers and excavators.
- Stripping the topsoil. The topsoil is stripped and transported to a designated topsoil stockpile for later use in reclamation.
- Drilling and blasting are performed in open pit mining when the excavation equipment is unable to break the rock for loading. Drilling and blasting are carried out to free the rock from its host rock so that it can be excavated and loaded.
- After blasting, the rock is loaded onto hauling equipment and is then placed in predetermined locations according to the mining plan. It can go directly to a crusher, a temporary stockpile for ore, or a waste material stockpile (material that is uneconomical to process). The waste stockpile can be used as needed, such as for building dams, constructing mine roads, backfilling, etc.
Open pit mining is considered one of the easiest and most beneficial mining techniques for industry participants. Some advantages of open pit mining include:
- Easily implementable for high-volume production.
- Allows for easy extraction of desired ore grades.
- Lower mining safety risks compared to underground mining.
- Ability to utilize a variety of mining equipment tailored to specific needs, taking into consideration mining quantities, topography, and material conditions.
The execution of open pit mining should always be environmentally and ecologically oriented. Preservation of the natural environment and its biological resources can be achieved by:
- Conducting mining without diverting water from the mining area to the original forest.
- Directly implementing land reclamation upon completion of mining to reach the expected climax ecosystem.
- Restoring the topsoil layer or surface soil layer to the uppermost layer with a specific thickness, enriching it with lime, organic fertilizers, inorganic fertilizers, and biological fertilizers.