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Coal Pillar Stooping - Assessing the Stability of Snooks

A bord and pillar mining layout on the No. 4 Seam will have a typical extraction ratio of approximately 60%. With the partial pillar extraction (stooping process), the overall extraction ratio would typically increase to approximately 75%, which makes it economically viable provided that it can be carried out safely.

An integrated risk management approach for underground coal pillar ...

Analysis for pillar extraction potential (A-PEP) is an intelligent tool, which could be used as a preliminary output indicator when considering the secondary extraction of regional support pillars in the Witbank and Highveld coalfields of South Africa.

Bord-and-pillar mining explained - Illawarra Mercury

Two main methods of extraction are used for underground coal mines in New South Wales: longwall and bord-and-pillar extraction. Bord-and-pillar extraction is the older of the methods, and .

Task 2.4 Underground trials of Seismic-Counter and goafing ...

constitutes the biggest problem in developing a practical tool for use in pillar extraction. The problem is addressed through signal conditioning and optimum placement of the sensing unit. Initially it was thought that the input parameters of GoafWarn would vary in different geotechnical areas.

An integrated risk management approach for underground coal pillar ...

Analysis for pillar extraction potential (A-PEP) is an intelligent tool, which could be used as a preliminary output indicator when considering the secondary extraction of regional support pillars in the Witbank and Highveld coalfields of South Africa. The safe and economic extraction of underground coal pillars is of paramount significance and ...

An integrated risk management approach for underground coal pillar ...

(except for the NEVID method). (Incidentally, NEVID is an acronym named after the inventors of the mining method—Neels Joubert and David Posthma.) As this research attempted to develop a design methodology for pillar extraction to increase the utilization of coal resources, looking at the history of pillar extraction in

Room and Pillar Mining - an overview | ScienceDirect Topics

The major partial mining method are strip pillar mining, Wongawilli strip pillar mining, room and pillar mining, and thickness-limited extraction. 1. Strip pillar mining. Strip mining technology is an effective measure to reduce the overburden strata and surface movement and deformation, and it is also one of the important measures in the system of "Green Mining."

Extraction of Pillars | PDF | Coal Mining | Mining - Scribd

Nevid pillar extraction method has been identified as one of the potential methods to be used in pillar extraction. However, this method has usually been applied at greater depths (>150 m) by . As part of this study a detailed investigation of the application of Nevid method at shallow depths was conducted.

SciELO - Scientific Electronic Library Online

SciELO - Scientific Electronic Library Online

Managing the geotechnical and mining issues - doczz.net

Transcription . Managing the geotechnical and mining issues

(12) INTERNATIONAL APPLICATION PUBLISHED UNDER World Intellectual ...

(54) title: pillar extraction mining method 1 0 a - 1 0 c 1 7 2 3 figure ...

The strength of hard-rock pillars - Rocscience

Pillars can be defined as the in situ rock between two or more underground openings. Hence, all underground mining methods utilize pillars, either temporary or permanent, to safely extract the ore. In coal mines rectangular pillars are often designed in regular arrays such that should a single pillar inadvertently fail the

Coal Pillar Stooping - Assessing the Stability of Snooks

A study was undertaken to investigate the potential to increase the overall extraction ratio through safe partial mining of the existing underground pillars on the No. 4 Seam at a colliery located in the Witbank Coalfields using a modified NEVID system. A bord and pillar mining layout on the No. 4 Seam will have a typical extraction ratio of approximately 60%. With the partial pillar ...

COAL PILLAR STRENGTH AND PRACTICAL COAL PILLAR DESIGN CONSIDERATIONS

included in a numerical pillar design model, other issues, such as gob formation, load transfer, material properties, and geological variations, may make model formulation difficult. It seems that a hybrid method of the back-calculation and numerical approaches may provide a more effective and versatile pillar design method in the future.

Partial pillar extraction with controlled goafing of the superincumbent ...

Both the open-end lift and the pocket-and-fender methods of pillar extraction have been tried with little success because of problems with roof control and ground stability. The main reasons for the dif. ficulties are the coarse-grained sandstone roof, local weaknesses in the coal seam, and the rate at which the pillars were extracted.

Various methods of pillar extraction. | Download Scientific Diagram

If the pillar sizes within the range of 25.5-34.5m are usually worked by the split and fender method. Therefore, the double split and fender method becomes the most suitable choice for the...

Managing the geotechnical and mining issues - doczz.net

The group rock engineer at the time, Mr B. Vorster, employed a Modified NEVID method based on the pillar extraction mining method developed by Mining.10 This method of pillar extraction was then carried out at Spitzkop Colliery, ATC, and also later at Boschmans Colliery, with no recorded cases of a CM burial or any windblast accidents.

Pillar Extraction | SpringerLink

Pillar extraction, (also referred to as retreat mining; pillar recovery; stooping; pillar robbing; and bord and pillar second workings) is the practice of forming a series of pillars and then partially or totally extracting some or all of the pillars, usually with mining operations retreating out of a panel. There are a number of basic pillar extraction methods, with numerous permutations ...

Volume- 6, Issue-2, Feb.-2018, COAL PILLAR EXTRACTION BY ...

After development of pillars in the Bord and Pillar method consideration has to be given to the extraction of coal pillars; which is known as pillar extraction or depillaring. In the process of pillar extraction, the extraction line should be so arranged as to facilitate roof control. Diagonal line or step diagonal line of

COAL PILLAR EXTRACTION BY CONTINUOUS MINER USING FISH AND TAIL METHOD ...

After development of pillars in the Bord and Pillar method consideration has to be given to the extraction of coal pillars; which is known as pillar extraction or depillaring. In the process of pillar extraction, the extraction line should be so arranged as to facilitate roof control. Diagonal line or step diagonal line of

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method used in extracting gold in ghana. method used in extracting gold in ghana. News. nevid method of extracting pillars . Coal Mining Methods EMFI Colorado School of Coal Mining Methods extracting pillars and allowing the roof to fall However, this is a complex procedure that requires additional planning Extract Method SourceMaking Extract Method...

(PDF) Problems and Control Measures of Horizontal Stresses in ...

Rock at depth is subjected to stresses resulting from the weight of the overlying strata and from locked in stresses of tectonic origin. When an opening is excavated in this rock, the stress field...

EVALUATION OF BORD AND PILLAR MINING SYSTEM IN MCL COAL MINES

proposed mine, extraction of the desired materials. One of such methods is the Bord and Pillar method of mining. Bord and Pillar method of mining is one of the oldest methods of mining. The success of Bord and Pillar mining is selecting the optimum pillar size. If the pillars are too large, then the extraction ratio decrease

Pillar Extraction - an overview | ScienceDirect Topics

In room and pillar mining, pillar extraction can be so designed that mined out area is submerged in water. This provides excellent inertization but is possible only in highly inclined coal seams. Most commonly, self-inertization is provided by the methane gas released from coal seams in the gas emission space.

D. Pillar extraction at Usutu Collieries using continuous miners

cars, and face drills. The method of extraction consisted of splitting the pillar and extracting the two fenders. This method proved very successful but had the follow-ing disadvantages. (a) Blasting caused the immediate shale roof to deterio-rate. (b) A minimum of 5 pillars had to be mined in various stages of extraction at the same time. This ...

Risk management of underground coal pillar extraction in South Africa ...

Analysis of Pillar Extraction Potential (A-PEP) is an intelligent tool that could be used as a preliminary output indicator when considering the secondary extraction of regional support pillars in the Witbank and Highveld coalfields of South Africa.

nevid method of extracting pillars - ivographic.nl

Aug 12, 1980 0183 32 A method of sublevel caving and pillar and top coal extraction for mining thick coal seams includes the advance mining of rooms and crosscuts along the bottom of a seam to a height of about eight feet, and the retreat mining of the top coal from the rooms, crosscuts and portions of the pillars remaining from formation of the rooms and cross-cuts...

Research Online - University of Wollongong

Research Online - University of Wollongong

Depillaring: Arrangement, Precautions and Pillar Extraction Method ...

The arrows indicate the direction of attack by miners. The smaller pillar M indicates the fender or Chowkidar, that is, the solid coal of stook or pillar left intact during extraction of the stook or pillar. Roman numerals indicate the sequence of extraction of pillars and stooks. (a) Roof is good and reliable. (b) "Half moon method". Roof ...

Pillar Extraction - an overview | ScienceDirect Topics

Unfortunately, the direct attack method only allows the CM to extract 8 m or so from each side of the pillar. An alternative to the direct attack is to enter the pillar and then gradually work the CM to a greater angle of penetration into the pillar, in much the same manner as turning a crosscut.