Description
Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of surface miners are manufactured today based on cutting drum placement and design specifications. Selective mining without drilling and blasting, high production and small size products are some of the prominent attractive features obtained with these moving marvels. This machine can be used with good efficiency in soft to medium hard rock (100–120 MPa) (Prakash et al., 2013).
Continuous surface miner is basically a cutting machine used in surface mines. These machines have been developed during 1970s primarily for extraction of this seams (not less than 2.5 cm thick) and selective removal of thin dirt bands present in seams (Surface Miner, 2019).
Drilling and blasting operations are a constant feature of the mining industry. They generate noise and environmental pollution through the uncontrolled release of dust into the atmosphere. One of the most dangerous consequences of these activities is the phenomenon of flyrocks, which can sometimes result in loss of life. Although mining companies have made significant efforts in recent years to implement strategies to mitigate these risks, the costs remain substantial. Surface mining offers a technological solution to optimise these costs, although it is not suitable for all types of mines.
Technical aspects of surface miners
The surface miner mainly consists of 5 units:
- Mainframe: it consists of operator’s cabin, supporting frames, boom counterweight, slewing.
- Conveying unit: it consists of two stages conveyors; one carries the material from the cutting drum and discharge on the boom conveyor. This conveyor in turn conveys it on the trucks.
- Drive unit: it consists of diesel operated engine whose power is transmitted to the cutting drum vis robustic belts drive. And it consists of hydraulic system to operate other units.
- Crawler unit: based on the design, it may be single pair or two pair crawlers.
- Cutting unit: the most important parameter is the cutting tool. The selection of right cutting tool is essential for good cutting performance & high life, since it constitute a major portion of the machine. The cutting depth can be system mounted on the machine, the preselected cutting is maintained either automatically or manually.
Based on the cutting principle and position of the drum, the surface miner is classified in three types: machine with middle drum configuration, machine with front boom cutting drum, machine with front cutting wheel.
The working principle of a surface miner
The surface miner is crawler-mounted machine having a cutting drum located b/w two sets of crawlers and positioned at the center of the machine. The drum is lowered and raised by hydraulic system with powerful motors thereby varying the depth of cut. The material cut is loaded onto the primary and secondary discharge conveyors for loading the same on to the loading/transporting equipment. The rear crawler travel at lower level then the front crawlers to adjust to the required depth (Surface Miner, 2019).
Surface miners vs Drill & blast (Introduction to Surface Mining, n.d.)
| Surface miners | Drill & Blast |
| Produce a smaller, more consistent particle size. | Produce larger, inconsistent particle sizes. |
| Help eliminate the primary crusher step. | Requires the use of a primary crusher. |
| Help reduce fines to increase usable product. | Results in fines and unusable product. |
| Increase payload in mine trucks over drill and blast material. | Lower payloads in mine trucks. |
| Access areas of surface mines where drilling and blasting cannot be done because of physical or permit limitations. | Restricted use in many areas limits material access. |
| Produce a smooth floor to help minimize wear and tear on mine trucks and loaders. | Creates volatile mine floors and conditions. |
| Help operations work next to power lines, pipelines, urban areas and other existing structures. | Cannot be performed near power lines, pipelines, urban areas and other existing structures. |
| Mine reserves that otherwise may be left behind. | Often results in mine reserves being untouched or left behind. |
| Help get the mine or quarry to market faster. | Can be slower to get the mine or quarry to market. |
Reference
Introduction to Surface Mining. (n.d.). Retrieved December 3, 2024, from https://www.vermeer.com/na/surface-mining/introduction
Prakash, A., Murthy, V. M. S. R., & Singh, K. B. (2013). Rock excavation using surface miners: An overview of some design and operational aspects. International Journal of Mining Science and Technology, 23(1), 33–40. https://doi.org/10.1016/j.ijmst.2013.01.006
Surface miner. (2019, December 30). SlideShare. https://www.slideshare.net/slideshow/surface-miner-212861342/212861342
