Once the deposit has been fully mined, perhaps the most common option is "retreat mining." This method has been criticized in recent years because it's extremely risky both to workers and local geology.. This technique involves strategically removing the remaining pillars, causing the roof to collapse and the productive area to be filled in by …
قرأ أكثر
Bord and Pillar method of underground mining has been used extensively to develop Indian coal seams into pillars and galleries. This results in only 20–30% recovery of coal and rest coal remain locked …
قرأ أكثر
namely: Bord And Pillar Base and Longwall System Base. The National Coal Development Corporation (NCDC) was formed in the year 1956 which initiated a number of trails with global cooperation. 2.1.1 Bord and Pillar Based systems: Multi stage/slicing was a variant of conventional bord and pillar method in
قرأ أكثر
The stability of the pillars is most important, particularly for undersized pillars (one of the cases may be widening and heightening for CM operation) as far as strata issues are con - cerned. In India, the CMR of India provides the guidelines for designing the pillars with respect to the width of the gallery and depth of cover [2].
قرأ أكثر
French Lorraine iron ore accounts for 94% of the total production, while 58 mines in Lorraine are mined by the room-and-pillar method. In the United States, the method is used by 65 percent of ...
قرأ أكثر
The nation's standard of living depends on its quantum of production and use of natural resources, including coal. Coal plays a major role in the development of a country like India. India has great potential of producing coal economically. Unfortunately, even after the nationalisation of 50 years of major Indian coal mines, we still have lower …
قرأ أكثر
different methods have been approached keeping in mind the production and safety. One of such methods is the Bord and Pillar method of mining. Bord and Pillar method of mining is one of the oldest methods. The key to the successful Bord and Pillar mining is selecting the optimum pillar size. If the pillars are too small the mine will collapse.
قرأ أكثر
continuous miner and its success in bord & pillar method of underground coal mining. * Professor, Dept. of Mining Engg., National Institute of Technology Karnataka, Surathkal
قرأ أكثر
The bord and pillar method is commonly employed in Indian underground coal mines, and the extraction rate varies between 30 and 65%. During pillar extraction, pillars are subjected to severe ...
قرأ أكثر
The study focuses on the implementation of mass production technology using a Continuous Miner (CM) with an increased cutting height to extract a 5.4m thick coal seam in a single pass (CIMFR Report, 1999). The seam has a remarkably short incubation period of just three months and is developed along the floor in a Bord and Pillar pattern.
قرأ أكثر
In India about 90% of underground production comes from Bord and pillar and the rest comes from Longwall (?). Further in our country a huge reserve is standing …
قرأ أكثر
Here the circumstances of bord and pillar mining are to face difficult surroundings, mainly, due to rock-mass characteristics and stress conditions of the deep horizon. ... As stated above, most of the underground coal production in India is made, mainly, by pillar formation. Therefore, underground extraction of standing pillars is the …
قرأ أكثر
The size of chain pillars in the Indian geo-mining conditions is primarily decided in accordance with the regulatory provisions. These provisions are of little help for deep longwall workings, exceeding the cover depth of 360 m. Furthermore, these provisions are primarily meant to support pillars in bord and pillar workings. They may not be …
قرأ أكثر
Presence of massive roof strata played an important role for the development (primary extraction) of large number of coal seams on bord and pillar. …
قرأ أكثر
CW: The primary benefit of bord and pillar mining is that for an equivalent production the capital cost of a bord and pillar operation would be 45% to 65% of that of a longwall mine. The operating costs may be 30% to 60% more than a longwall, but the risks are significantly less and production variances are very low compared to longwall.
قرأ أكثر
The UG2 reef was chosen for bord-and-pillar application due to its higher reef width, which implies less dilution. There are two current bord-and-pillar projects at Amandelbult, 16 West and 43 East. This project is aimed to design a bord-and-pillar layout section for the lower part of the farm Vlakpoort and the upper
قرأ أكثر
The current trend in coal production in India shows that underground mining contributed less than 5–8% of the total coal produced. ... Bord and pillar in India adopted induced caving of roof ...
قرأ أكثر
In India, about 98% of underground output of coal is obtained by Bord and Pillar method and barely about 2% by longwall methods. The other countries where Bord and Pillar method predominates are Australia, USA and South Africa. 2.2. Bord and Pillar Method Fundamentally, the bord and pillar method of mining coal
قرأ أكثر
For, example, the majority of underground coal mines were developed by Bord and Pillar (B&P) method in which the size galleries are restricted to 4.8 m × 3 m …
قرأ أكثر
Fig.1: Extraction of Pillars. 3.2 Design of Bord and Pillar Workings The main elements of Bord and Pillar workings are: Size of the Panel The main consideration in deciding the size of the panel is the incubation period of the coal seam. The size is so fixed that the
قرأ أكثر
opencast pillar mining in previously mined underground bord and pillar workings by P.L. Ngwenyama1 and W.W. de Graaf1 Synopsis South Africa is one of the leading producers and exporters of coal globally. A significant amount of the country's production is obtained from previously mined underground bord and pillar workings. This
قرأ أكثر
Subchapter 1.2 - Exploration of mining method for coal extraction in developed bord and pillar property by powered support long wall equipment. ... In India its introduction and successful operation of such short longwall mining, termed as "shortwall mining" in one of its underground coal mines, to liquidate developed pillars using …
قرأ أكثر
Explosives and Detonators: Only permitted explosives, such as P5 type (e.g., Pentadyne-HP), are used.These are non-incendive and suitable for methane-rich environments. Blast Timing: The Coal Mines Regulations 2017 limit the duration of an underground blast to 150 milliseconds in Degree I and II gassy seams and 100 …
قرأ أكثر
Pillar extraction is the m ost extensive exercise in both Bord and Pillar and Room and Pillar ... thereby improving both production and productivity. India has tremendous potential to introduce ...
قرأ أكثر
Bord and pillar mining The following methods are commonly used in bord and pillar method for development and depillaring using continuous miner: Development 1. Bord and pillar method Depillaring 1. Split and Fender system 2. Nevid method of mining Continuous miner A continuous miner is a large steel drum equipped with a
قرأ أكثر
Download scientific diagram | 9: Illustration of Bord and Pillar Mining Method (Van der Merwe, 2011-As modified by student) from publication: EVALUATION OF PILLAR DESIGN SYSTEMS FOR LOW REEF ...
قرأ أكثر
Though longwall technology was introduced in India in the year 1906-07, it was only since 1978 that the technology has been planned for bulk production by introduction of powered roof supports ...
قرأ أكثر
awareness of the capacity of fully mechanised bord and pillar system using mass production technology with continuous miner and shuttle cars. In conventional mining …
قرأ أكثر
Any bord and pillar platinum mine thrives on effective design of bords and pillars. Pillars have to be large enough to ensure safety and small enough to ensure economic and sustainable ...
قرأ أكثر