Underground mining, Coal Prep Plant, and Strip Mining - Essay Example

?Underground Mining Excavation of hard and soft minerals from underground is achieved through underground mining. Underground mining is undertaken differently in different regions depending on the specific mineral that is being mined. Methods and equipment used to access underground also vary in this respect. However, there are commons methods and techniques used to access underground. Accessing underground is done through declines, shafts, and adits (Hustrulid 318). Spiral tunnels that circle the deposit flanks or those that are sunk around the deposit being mines are referred to as the declines. These tunnels are sunk from the surface to allow access the underground. Declines can also be sunk where an open cut mine already exists, and the tunnels are made on the wall of the already open mine. Vertical excavations that are sunk close or adjacent to mineral deposits are referred to as the shafts. In most cases, they are sunk for both access to underground and shaft haulage purposes. On the other hand, adits refer to horizontal or near horizontal excavations made on hills or mountains (Hustrulid 403). Use of ramps is also common when it comes to accessing underground. Seams that are mined must be consistent with the set regulatory provisions enforced by mining regulating agencies. The miner also assesses the mine and the deposit available for mining. The thickness of the seams must be significantly adequate to initiate the mining project. This means that the deposits being mined must be in a position to compensate all the mining costs and earn relevant profits for the mining firm. The properties of the deposits contained in the seams must at least meet the minimum requirement of the mining entity in terms of their composition and value. Different machines and equipment are used for underground mining. The equipment to be used is determined by the method of mining to be used and the form of underground access to be employed. Drills, excavators, and mining shovels are just but some of the equipment used for underground access. Trucks are also used for transport purposes whens soil dug from underground have to be moved. Cranes and lifts are used for different purposes, ranging from lifting machinery and mine workers during the mining process. Conveyor belts are also used to move different materials to different locations, especially the mined minerals. Most importantly, tunnel boring machines are used for the purpose of sinking shafts or declines, and belt systems are fitted underground to facilitate different aspects of the mining process. Equipment used for underground mining can vary from one mine to another depending on the mineral being mined. Ventilating super sections requires an assessment of ground stability before the ventilation is undertaken. Hard and soft ground and underground surfaces are determined, and the right position of super section ventilation determined. Once this is complete, the plan is implemented bit by bit, while assessing the impact of the process on the mining site. This assessment relates to safety and position of the deposit to be mined. Machinery and equipment are then put in place and the ventilation is made, taking into account all risk factors in super section ventilation. Coal removed by miners is transported to the washing plant in various ways. This depends on whether the washing plant is installed on the surface or underground. Mined coal reaches the washing plant through conveyor belts or through track transportation. Deposits from continuous miners are collected and loaded on conveyor belts or on tracks that transport them to the washing plant. However, use of tracks is only employed under instances where the process is economical. Shaft haulage and belt systems are also used where the mined coal has to be taken from the mining point to a washing plant located on the surface (Hustrulid 551). The visit to the mine was informative and educative in terms of underground mining and preparation of plants to facilitate the process. The mining process encompasses coordination of numerous activities, all of which are designed to achieve the desired outcome. Professionals from different engineering and construction fields combine their expertise and work together to ensure that the underlying duties and responsibilities are undertaken. The complexities and concerns in mining were highlighted, especially in relation to risk factors, safety of miners, and social, economic, and environmental issues in mining. Safety is a core concern when it comes to mining. Miners are expected to observe all safety measures and procedures without exception. The required working gear must be used at all working times, and all safety precautions must be adhered to. The management team oversees the implementation and observance of safety measures and policies. Emergency occurrences are critically provided for, and emergency response team remains watchful at all times during the mining process. Coal Prep Plant Coal washing plants employ up to six basic circuits, which include Jig, Dense Medium Vessel, Dense Medium Cyclone, Water-Only Cyclone, and Table, Froth Flotation (Arnold, Klima & Bethell 85). The choice of the specific circuit to use rests with the mining company, depending on the coal deposits being dealt with. Jig circuit is the most commonly used by many coal washing plants. In this circuit, raw coal is fed to the washing plant using conveyor belts. Once the raw coal reaches the plant, it is sluiced into a Baum jig and clean coal, refuse product, and middling product are produced (Arnold, Klima & Bethell 119). Clean coal is then separated from the other two products using bucket elevators that drain off excess water from the refuse and middling products. Sorting of clean coal according to fine, middle, and top sizes follows, and they are processed accordingly. The middlings are taken back to the plant’s entry point and reprocessed according to the applicable specifications. Water streams, electricity, electricity motors, low pressure air and raw coal are the primary components that constitute jig circuit’s operations (Arnold, Klima & Bethell 173). The jig circuit is made up of a number of cells that hold different materials at a given point in time, and where water and air are introduced at controlled series to facilitate coal cleaning. The final product is separated from the refuse and any available middling product at the end of the washing process. The jig circuit is summarized by the figure below: Strip Mining Strip mining is a form of surface mining that is primarily employed in mining minerals that are close to the surface, but are buried under one or more rock and/or dirt layers (Marjoribanks 138). Before the actual mining starts, the site is cleared to allow easy access by the miners and their machinery and equipment. Dumping of the dug waste is then done in the predetermined dumping ground. Drilling follows through the layers that occur over the mineral deposits, which can be made of rock or dirt. Numerous holes are sunk across the site. After that, explosives are fitted in the drilled holes and blasted to allow access to the mineral deposits (Marjoribanks 154). Once access to the mineral is gained, it is broken into sizes that can be moved by heavy machinery. The mineral is mined in long and narrow strips, and the miners only move to the next strip once one strip is fully mined. Strips are then filled using the dug wastes, and the mined mineral is transported to the processing plant. Reclaiming and/or rehabilitating land after mining is necessary in trying to restore the land’s productivity. Mining causes environmental degradation, an aspect that environmental agencies are strict about in regulating mining activities. Mining companies are required to adhere to the regulatory provisions enforced by the various agencies that monitor mining activities. Land reclamation and/or rehabilitation involve restoration of land to a productive state after mining is completed. This entails filling open ground, tunnels, or shafts. At the start of mining, the vegetation is cleared to pave way for miners and their machinery. When the mining is completed, the land is rehabilitated and/or reclaimed by replanting vegetation cover and most importantly trees. Where forests are cleared for mining activities, afforestation and/or reforestation activities are undertaken. Finally, mountains of dumped wastes are leveled or used to fill open mines after mining is completed. Works Cited Arnold, Barbara., Klima, Mark & Bethell, Peter. Designing the Coal Preparation Plant of the Future. New York: SME, 2007. Hustrulid, William. Underground Mining Methods: Engineering Fundamentals and International Case Studies. New York: SME, 2001. Marjoribanks, Roger. Geological Methods in Mineral Exploration and Mining. New York: Springer, 2010. Read More