Coal underground mining methods pdf

When coal seams are near the surface, it may be economical to extract the coal using open cut also referred to as open cast, open pit, mountaintop removal or strip mining methods. Opencast coal mining recovers a greater proportion of the coal deposit than underground methods, as more of the coal seams in the strata may be exploited. Coal is usuallyrecovered from underground mines in either of two methods. For each state, stand alone preparation plant hours are distributed across mining methods by the proportion of underground hours for all stand alone mines. It is defined as a concentration of minerals that can be exploited and turned into a saleable product to generate a financially acceptable profit under existing economic conditions. Other underground coal mines are laid out in a checkerboard of rooms and pillars fig 2 and the mining operation involves cyclical step bystep mining sequences the rooms are the empty areas from which coal has been mined and the pillars are blocks of coal generally 40 to 80 feet on a side left to support the mine roof. Minerals derived from magma were generated in the depths of underground.

Recognised standard 12 place change mining operations in underground coal mines, department of natural resources and mines, 2015 1. There are generally two ways in which systems are costed, viz. An underground mine consists of the portals entrance and exits to the mines, mains, submains, panels, and working faces. Coal mining began in indiana in the middle 1800s using the underground mining method. Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice. Underground mining methods handbook sme pdf free download free books online. This successful operation may be achieved if the geological and mining conditions prevailing in the colliery area are considered thoroughly during the stage of mine planning and design. Longwall mining and roomandpillar mining are the two basic methods of mining coal underground, with roomandpillar being the traditional method in the united states.

The time to plan for subsidence impacts is well before mining begins, not after surface effects are noticed. Both methods are well suited to extracting the relatively flat coalbeds or coal. New technology has enabled greater productivity and safer mining in underground operations, which has also helped decrease the cost of such production methods. The various methods of mining a coal seam can be classified under two headings, surface mining and underground mining.

During the history of the mine, rapid variations in seam heights. Underground mining methods 1 foreword in history, before miners had access to productive equipment minewide, are benefiting from experience gained by tunnel and blasting agents, mining. Numerous coal winning methods have been used on the mine during its four years of existence. Mining engineering interview questions with answers pdf free download. Underground mining is usually by the roomandpillar mining or longwall mining method. Advances in longwall mining method have made this system more economically attractive because of its efficiency and production potential. Due to advancements in technology and modern coal mining techniques, the current coal dust particles in intake airways are. The panels are the working sections of the production operation. Coal national energy education development project. Year ug production mm percentage underground surface production mm 1930.

In this method, a number of parallel entries are driven into the coal seam. This is to certify that the thesis entitled evaluation of bord and pillar mining system in mcl coal mines submitted by sri ram chandra nayak, roll no. Underground mining methods vary according to the site conditions, but all. It deals with the exploitation of coal seams of different thicknesses and dips occurring in a variety of. Principles and practices of modern coal mining is a comprehensive text book on the theory and practice of coal mining. Modern underground coal mining methods can be classified into four distinct categories. The mines are now operating at significantly higher annual tonnages, growing deeper, more complex and. Depending on the mining method, a working section can have one or more working faces. Southern african diamond mines typically used underground mining methods. The high productivity being achieved by longwall mining demonstrates its potential for being a substantial segment of underground coal. In alaska underground mining was the primary form of coal mining used until about the late 1930s early 1940s i was unable to find an exact date. Pdf coal mining methods researchgate coal mining methods, their auger mining uses largediameter drills mounted on m obile equipment to bore into a coal the details of all publications are in the researchgate in full text pdf underground mining methods and equipment. Sul l ivan2 abstract a series of geological surveys were completed in six coal mines in connection with a bureau of mines research program on methane control.

Underground mining currently accounts for a bigger share of world coal production than opencast. The cutting action of an auger differs from other coal cutting machines, such as continuous miners, in that it exploits the lower tensile strength of coal rather than. The current methods must be judged on the economic factors and their advantages and disadvantages. Recognised standard 12 department of natural resources. Niosh recently conducted a comprehensive survey of us underground coal mines to determine the range of coal particle sizes found in dust samples collected from the mine entries.

Underground mining methods 1 foreword in history, before miners had access to productive equipment minewide, are benefiting from experience gained by tunnel and blasting agents, mining was hard and hazardous manual contractors, who frequently have to concentrate their focus work. Depending on the mineral being mined and the nature of the deposit, there are many different underground mining methods that can be implemented. Geologic investigations of underground coal mining problems. The room and pillar system is used in mining coal, gypsum, iron, and uranium ores, particularly when found as manto or blanket deposits. The success of the operations of longwall mining as one the the conventional underground coal mining methods is highly dependent upon the mine design and layout. In this thesis, the existing geomechanics classification bieniawski, 1979 was modified for use in underground coal mines through the introduction of adjustment modifiers for strata weathering, horizontal stress, and roof support.

Room and pillar mining was one of the earliest methods used, although with significantly more manpower. The choice of mining method largely depends on the geology of the coal deposit. It has a lot of commercial and industrial applications. Continuous mining also called bord and pillar is a mining system in which the mined material is extracted across a horizontal plane while leaving pillars of untouched material to support the. In surface mining, the topsoil and layers of rock are removed to expose large deposits of coal. Underground mining methods are employed when the depth of the deposit, the stripping ratio of overburden to ore coal or stone, or both become excessive for. Plotmaker mining methods blackout day presentation 5 th december 2008 venkat m. Bituminous coal was first discovered in indiana along the wabash river in 1736.

Underground coal mining books pdf kaseo heavy machinery. Both methods are well suited to extracting the relatively flat coalbeds or coal seams typical of the united states. Minerals and mineral products are the backbone of most industries. Which cut is used for solid blasting in indian coal mines. As a result of changes that have been occurring in the underground coal industry in the us, the continued overexposure of workers to respirable dust, and recent xray findings, the need to improve existing dust control technology and develop new control methods remains a major focus for niosh and the us mining industry. Underground coal mining methods and engineering dust controls. The various methods of mining a coal seam can be classified under two headings, surface.

In the early 1900s, steam powered mining equipment became the dominant method of coal removal. Team lead minex, india slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Surface and underground coal mining are broad activities that incorporate numerous variations in equipment and methods, and the choice of which method to use in extracting a coal seam depends on. Comparison of designs for the dewatering of coal, gold and.

It is an energy giving nonrenewable source of energy. Geologic investigations of underground coal mining problems by c. Coal is an organic sediment consisting of a complex mixture of substances. By the new stone age,humans had progressed to underground mining in systematic openings 2 to 3 ft 0. Water control in underground mines grouting or drainage.

Underground mining methods and applications production headframe hans hamrin 1. A coal mining method that accounts f or less than 1% of deep coal production, shortwall involves the use of a continuous mining machine with mov eable roof supports, similar to longwall. Because subsidence due to underground mining may be inevitable, the relevant questions to be asked are how much, when, and where, and. Surface mining can be used when the coal is buried less than 200 feet underground. The first step in selecting the most appropriate mining method is to compare the economic efficiency of extraction of the deposit by surface and underground mining methods. Surface mining is used to extract about onethird of the coal in the united states. Even in mines where the longwall method is the principal extraction method, the development of the mine and the longwall panels is accomplished by roomandpillar continuous mining.

Advancements in technology primarily hydraulics and explosives and expansion of mining activities in the west particularly in the prb, have shifted mining trends from underground to surface production over the past 40 years. The method of surface mining was first recorded being used in the healy river area where it is still in use by the usibelli coal mine. A new underground auger mining system to over 2,000hp, hole depth increase to in excess of 200 m and production rates exceed 2,000 tonnes a shift. Underground mining methods vary according to the site conditions, but all involve the removal of. Pdf mining methods underground mining mayra garcia. Classification of underground mining methods mineral production in which all extracting operations are conducted beneath the ground surface is termed underground mining.

Underground mining methods are usually employed when the depth of the deposit andor the waste to ore ratio stripping ratio are. Mining of coal is one of the oldest industrial operation. It highlights the principles and describes the modern techniques of surface and underground coal mining citing examples from india and abroad. Coal and tar sands operations typically involve moving large amounts of waste. In open pit mining, thick seams tens of meters are mined by traditional quarrying techniques.