abutment stress width in underground mining
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abutment stress width in underground mining

New Abutment Angle Concept for Underground Coal Mining

New Abutment Angle Concept for Underground Coal Mining. Ihsan Berk Tulu ... = the extent of the abutment stress where 90% of the load falls. ... q = the insitu stress. P = the width of the panel. E. s = the elastic modulus of the seam.

CDC - Mining - Ground Stress in Mining Part 1 ...

Mining Publication: Ground Stress in Mining (Part 1): Measurements and Observations at Two Western U.S. Longwall Mines. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have been conducting research with the goal of gaining a better understanding of ground stress redistribution resulting from mining.

“Advance and Relieve” Mining, A Method to Mitigate the ...

the rear horizontal stress abutment (figure 16). This abutment did not advance with the mining, but remained stationary. In E15, the damage consisted of cutters that developed in the RI entry from the cave outby for a distance of approximately 60 m. This stress damage was parallel to the length of the cave. Stress damage also occurred in the ...

Abutment pressure distribution for longwall face mining ...

Jan 01, 2019  Front abutment pressure is the result of in-situ stress was readjusted for a new state of equilibrium in the longwall mining process. Research on the distribution of abutment pressure has significant importance in confirming the width of the coal pillar and

Vertical stress changes in multi-seam mining under ...

Jul 01, 2013  Highlights Numerical methods are used to evaluate stresses under supercritical longwalls. Abutment angle of first mined seam significantly affects the maximum vertical stress. Multi-seam mining stability depends on pillar width as well as the OB/IB ratio. Larger vertical stresses at depth are observed for transversely isotropic rocks. The coal friction angle and UCS have little effect on the ...

NUMERICAL MODELLING OF MULTIPLE-SEAM COAL MINING

by coal pillars and abutment pressure zones in front and to the side of the longwall panel. The parameters of high-stress zones depend on the mining depth, the deformation properties of the interburden and the seam being mined, the pillar width, and the

Stress induced damage in tunnels in a cave mining ...

Stress induced damage in tunnels in a cave mining environment in kimberlite for an extraction ratio of 13 per cent. Excavations remove a minimum of 45 per cent of the rock on the extraction level depending on tunnel size and the accuracy of tunnel development. Once the troughs have been developed at least

Longwall Mining Method and Design

Transfer of stress to developments mining beneath the abutment, can occur through the pressure bulb effect, The abutment is a high-stress zone usually occurring where the gob and solid coal meet. Unlike the uniformly loaded pillars in the example in figure 5, the abutment stress profile is characterized by peaks and troughs, with the peak ...

Pillar design - QueensMineDesignWiki

The edge of the shaft pillar will be highly stressed as it is an abutment to mining, but the interior is mostly at a uniformly lower stress level. The following graph is based on the previous one, in which the constant interior stress magnitude region is used as a design constraint.

Development planning for the Oyu Tolgoi panel cave mine

The Hugo North orebody is approximately 225 m wide, 2,000 m long, and 1,000 m high. The underground project currently underway is the planned first lift of the orebody, with a lift height of +500 m and an average column height of 350 m. The mining rock mass rating (MRMR) of Lift 1 is 40–45, and has a predicted critical

A new theoretical method for calculating front abutment ...

Nov 19, 2019  The mining disturbance of the working face causes abutment stress in the surrounding rocks of the stope and roadway 1-7 and induces deformation and destruction of the surrounding rocks, even inducing dynamic disasters such as coal burst and rock burst. 8-10 This has an impact on underground equipment and production systems and poses a threat to ...

APPENDIX II

stress distribution around underground excavations is ... width is reduced the high abutment stress concentrations ... completion of mining operations the final stress distribution existing in the interpanel pillar is of the form depicted in Fig. 11.6(b). II .4 Conclusions: -'';v ^ # 1

Investigation of Rib Pillar Stability at Ömerler ...

around underground mining excavations in comparison to other numerical techniques. (Itasca 1997, Yaşıtlı Ünver 2005). ... abutment stress formed at a distance of 7 m in front ... width of the rib pillar between M2 and M3 panels

Rock burst criteria and control based on an abutment ...

the roadway. The transferred stress is superimposed with the pre-existing in situ stress in the surrounding rock, as shown in Figure 4A,B, increasing significantly the chance of rock bursts. To construct the abutment-stress-transfer model, the over - lying strata are regarded as

Mining-Induced Failure Criteria of Interactional Hard Roof ...

Abstract: Due to the additional abutment stress, interactional hard roof structures (IHRS) affect the normal operation of the coal production system in underground mining. The movement of IHRS may result in security problems, such as the failure of supporting body, large deformation, and even roof caving for nearby openings.

DESIGN OF RIB PILLARS IN LONGWALL MINING BASED ON ...

The literature on underground mining stability can be divided into three categories describing theoretical, practical and experimental ... Vertical Stress(11) Peak Abutment Stress(12) Width of Yield Zone (13) Load Taken By xb (14) Where, F = in radians) k = Triaxial stress factor,

Pillar design - QueensMineDesignWiki

The edge of the shaft pillar will be highly stressed as it is an abutment to mining, but the interior is mostly at a uniformly lower stress level. The following graph is based on the previous one, in which the constant interior stress magnitude region is used as a design constraint.

Longwall Mining Method and Design

Transfer of stress to developments mining beneath the abutment, can occur through the pressure bulb effect, The abutment is a high-stress zone usually occurring where the gob and solid coal meet. Unlike the uniformly loaded pillars in the example in figure 5, the abutment stress profile is characterized by peaks and troughs, with the peak ...

Pillar design in coal mines - SlideShare

The normal stress perpendicular to the seam, And the average stress on the pillar, P or σp: Where, H = depth of cover, m B = width of the mined out area, m = unit rock pressure = 0.025 MPa/m of depth R = extraction ratio w = width of the pillar, m α = dip of the seam The value of k, which is the ratio of horizontal to vertical in-situ stress ...

Development planning for the Oyu Tolgoi panel cave mine

The Hugo North orebody is approximately 225 m wide, 2,000 m long, and 1,000 m high. The underground project currently underway is the planned first lift of the orebody, with a lift height of +500 m and an average column height of 350 m. The mining rock mass rating (MRMR) of Lift 1 is 40–45, and has a predicted critical

The Abutment Angle Model and Its Appropriate Use for ...

abutment load about the longwall panel, including stress balance approaches (e.g. Wilson, 1973 and 1981) as well as the use of surface subsidence profiles (e.g. King and Whittaker, 1971, Choi and McCain, 1980 and Mills, 2001) to assist in the evaluation.

EVALUATION OF UNDERGROUND COAL PILLAR DESIGN

Size of pillars 21 2.8. Laboratory Techniques 22 3. MATERIALS AND METHODS 3.1. Data collection 24 ... The two common methods of underground mining include Longwall mining and Bord and Pillar method of mining. The method mostly ... The ratio of strength of pillar to the stress

Method of Entry Layout under Synergistic Effects of ...

In underground mining engineering, rocks around the entry are always subjected to large plastic deformation disasters, such as supporting body failure, roof rock collapse, and even rock burst under abutment stress and dynamic stress. To improve the stability of these rocks, the entry layout under abutment stress and dynamic stress (ELAD) method was put forward to protect the entry from high ...

The Block Cave Mining Method - UKEssays

1.1 Block Caving. Block caving is an underground mining method applicable to the extraction of low-grade, massive ore bodies with the following characteristics: large vertical and horizontal dimensions, a rock mass that will break into pieces of manageable size, and. a surface that is allowed to subside. These rather unique conditions limit ...

APPENDIX II

stress distribution around underground excavations is ... width is reduced the high abutment stress concentrations ... completion of mining operations the final stress distribution existing in the interpanel pillar is of the form depicted in Fig. 11.6(b). II .4 Conclusions: -'';v ^ # 1

Investigation of Rib Pillar Stability at Ömerler ...

around underground mining excavations in comparison to other numerical techniques. (Itasca 1997, Yaşıtlı Ünver 2005). ... abutment stress formed at a distance of 7 m in front ... width of the rib pillar between M2 and M3 panels

The Abutment Angle Model and Its Appropriate Use for ...

abutment load about the longwall panel, including stress balance approaches (e.g. Wilson, 1973 and 1981) as well as the use of surface subsidence profiles (e.g. King and Whittaker, 1971, Choi and McCain, 1980 and Mills, 2001) to assist in the evaluation.

Chuquicamata underground mine design: the simplification ...

et al. 2012). In addition, it improves the mining area availability by reducing the need for secondary breakage and reducing the abutment stress (Molina et al. 2008; Osorio et al. 2007; Catalán et al. 2012). The use of high-capacity LHDs (with large buckets) tipping

DESIGN OF RIB PILLARS IN LONGWALL MINING BASED ON ...

The literature on underground mining stability can be divided into three categories describing theoretical, practical and experimental ... Vertical Stress(11) Peak Abutment Stress(12) Width of Yield Zone (13) Load Taken By xb (14) Where, F = in radians) k = Triaxial stress factor,

Pillar design in coal mines - SlideShare

The normal stress perpendicular to the seam, And the average stress on the pillar, P or σp: Where, H = depth of cover, m B = width of the mined out area, m = unit rock pressure = 0.025 MPa/m of depth R = extraction ratio w = width of the pillar, m α = dip of the seam The value of k, which is the ratio of horizontal to vertical in-situ stress ...

EVALUATION OF UNDERGROUND COAL PILLAR DESIGN

Size of pillars 21 2.8. Laboratory Techniques 22 3. MATERIALS AND METHODS 3.1. Data collection 24 ... The two common methods of underground mining include Longwall mining and Bord and Pillar method of mining. The method mostly ... The ratio of strength of pillar to the stress

Appendix Y - Glossary of Mining Terms as used in this ...

Abutment - In coal mining, (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides, which act as abutments of the arch of strata spanning the roadway; and (2) the weight of the rocks over a longwall face is transferred to the front abutment, that is,

Development planning for the Oyu Tolgoi panel cave mine

The Hugo North orebody is approximately 225 m wide, 2,000 m long, and 1,000 m high. The underground project currently underway is the planned first lift of the orebody, with a lift height of +500 m and an average column height of 350 m. The mining rock mass rating (MRMR) of Lift 1 is 40–45, and has a predicted critical

The Block Cave Mining Method - UKEssays

1.1 Block Caving. Block caving is an underground mining method applicable to the extraction of low-grade, massive ore bodies with the following characteristics: large vertical and horizontal dimensions, a rock mass that will break into pieces of manageable size, and. a surface that is allowed to subside. These rather unique conditions limit ...

Block Caving Cu-Au Porphyry

Mar 07, 2016  Cave Mining Cu-Au Porphyry. There are over 45 cave mining projects in various stages of studies and development around the world. Cave mining methods will be the underground method of choice in the future. It is only relatively recent that this mass mining method, despite 70 years of use, has begun proving its potential.

Stress/Strata Control - underground COAL

Stress/Strata Control Along the Longwall Face. Along the face, the roof control function is a matter of providing sufficient resistance to control the dead load of the mass of strata which is breaking, or has broken, away from the bulk of the overlying strata.

v118n7a8 Interaction between vertical stress distribution ...

zone, and IV – pre-mining vertical stress zone. The limit equilibrium zone x0 ranges from 3 to 20 m in width and is typically between 5 and 12 m, and can be calculated by (Quian Shi, and Xu, 2010): [1] where m is the mining height, f is the friction factor between the

NUMERICAL INSIGHTS INTO STRESS REDISTRIBUTION IN

changeable regularity of the abutment stress in the process of protected seam mining for methane control. The change rule of the abutment stress can be studied according to the stress redistribution in the mining stage. When protected seam is mined 20, 40, 60 and 280 m, respectively, the abutment stress distribution

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