Custom Crushers And Provide Solutions

An assessment of coal pillar system stability criteria

Jan 01 2017 0183 32 This issue simply dictates that other pillar system stability controls need to be put in place when developing a panel or mine layout that incorporate large numbers of coal pillars with w/h ratios of...

Coal Pillar Size of Ultra Closed Distance Seam and Layout

The support effectiveness of mining gateway at closed-distance seam is determined by the layout of mining gateway and the stress effect of the upper coal pillar load on the bottom seam The stress effect is affected by the coal pillar size and the properties of the coal pillar and surrounding rocks These factors may cause the variation of the stress concentration which could cause the...

PAPER OPEN ACCESS Related content Reasonable Width of

coal wall roof decreases slowly with the increase of the coal pillar width and the peak stress gradually closes to the roadway coal wall with the increase of the coal pillar width When the coal pillar width changes from 7 m to 10 m in which the roof peak stress transit to the upper coal pillar from the coal wall 0 5 10 15 20 25 30 35 40...

Three Dimensional Numerical modelling Of Coal Mine

depillaring method This pillar extraction method was implemented in RS3 to model the stress amplification due to an advancing goaf towards the observation point The modelled results were validated against the field measurements obtained for the case example A single sequential coal mine roadway model consumed 26GB of space and took...

Extraction of the remnant coal pillar in regular and

Sep 01 2018 0183 32 The left coal pillar are often fractured and have lower supporting capacity Thus the roadway excavated in the coal pillar would undergo severe deformation Limited studies have been conducted on the extraction of the left coal pillar Jin et al 2015 reported a study on roadway layout for mining the left coal pillar in room and pillar mine...

EVALUATION OF BORD AND PILLAR MINING SYSTEM IN MCL

1 Cross section of typical Bord and pillar layout 11 2 Type of machineries in pillar mining 12 3 The tributary area pillar loading concept 19 4 The pressure arch theory 21 5 Multiseam working exploiting the intra-dosal region of pressure arch 21 6 Methods of pillar extraction 26 7...

Study on Reasonable Size of Coal and Rock Pillar in

The deformation mechanism of the protective coal and rock pillar area outside a stope is an important parameter for setting a reasonable size In this paper based on the geological condition of working face 1231 1 in a mine in Huainan a method that combines the use of a borehole and Brillouin optical time domain reflectometry BOTDR was proposed to analyze the stress variation laws of coal...

Design of rib pillars in deep longwall mines based on

coal mines and reduce pollution caused by traditional cemented paste backfill In this mining method the width of the rib pillar between two longwall panels is important to maintain roadway stability prevent rockbursts and water seepage To design the width of rib pillars this study firstly established a T-shaped overlying strata structure...

Pillar design incoalmines

of bOld-and-pillar mining methods are widened to a coal-to-waste ratio of1 5and40percentlostcoal then almost 63per cent ofthe country s coal reserves fall within thescopeofbord-and-pillar mining From theabove discussion itfollowsthat considerable benefit canbegained fromacritical examination ofthe principles underlying thedesign ofcoalpillars...

Design of backfilled thin

In underground coal mining any increase in coal recovery rate is dependent on a decrease in pillar size Backfilling is one way of reducing the required size of pillars and hence the volume of coal left underground Therefore any comparisons made between a self-supported mine layout and backfill supported mine layout are based directly on pillar design The most effective way to examine the...

v118n2a9 Modelling coal pillar stability from mine survey

essential pillar design parameters ie the individual mining depth below surface H the pillar height h and effective square width we to each individual pillar in the database The latter parameter may be calculated from the pillar base area Ap and circumference C according to the equation provided by Wagner 1980 1...

Coal Pillar Design When Considered a Reinforcement

reinforcing coal pillar design representation the horizontal stress acting within the overburden the competence of the overburden in terms of its self-supporting ability across the panel and the panel width are all brought into the problem representation implications on bord and pillar layout design involving coal...

Room and pillar mines Mining Techniques Underground

The room and pillar system is used in mining coal iron and copper ores mainly when found as manto or blanket sediments stone and aggregates talc soda ash and potash The key to the winning room and pillar mining is opting the optimum pillar size If the pillars are so small the mine will fall down...

Innovative backfilling longwall panel layout for better

that non-pillar longwall panel layout cannot protect surface structures against damages at a relatively large mining height even though complete backfill is conducted In such cases separated longwall panel layout should be applied ie panel width should be subcritical and stable coal pillars should be left between the adjacent panels...

EMFI Energy and Minerals Field Institute

The Energy and Minerals Field Institute EMFI founded in 1978 designs and conducts programs to familiarize selected audiences with the realities of resource development in the Western United Stat...

Reasonable coal pillar design and remote control mining

However if the coal pillar width is too large as figure 3a shows it will waste the resource and reduce the resource recovery In general the reasonable width of coal pillar is shown in figure 3b exploit as much coal resource as possible under the safety condition of the pillars Figure 3 Plastic zone with different coal pillar widths...

Research on the Influence of Slurry Filling on the

Room-and-pillar mining is a commonly used mining method in previous practice in northwest China mining area Due to priority selection of high-quality resources coal mines in northwest China generally have to face upward mining above goaf Thus the stability of a floor coal pillar influenced by mining activities plays an essential role in upward mining above goaf...

ESTIMATION OF CAPITAL COSTS FOR ESTABLISHING COAL

14 Underground coal mining 9 141 Room and pillar 9 142 Longwall 12 15 South African coal mining context 13 151 History of the South African coal mining industry 13 152 Current status of coal mining in South Africa 15 153 The role of South African coal market plays globally 18 16 Purpose of the study 20 17 Context of the...

Site Browser

Pillar design Refine Your Search Equipment tools and parts Geographic regions Geologic conditions and events Hazard prevention and control Hazards and exposures Mine locations excavations and structures Mining types and methods...

9 mine diagrams

Room and pillar method coal mine NSW Australia This is a good diagram showing the method of coal mining where rooms are cut out leaving some coal pillars to keep the roof up The alternative is to advance a scaffold letting the roof fall behind...

DEVELOPMENTS IN COAL PILLAR DESIGN AT SMOKY RIVER

relating to layout mining and pillar dimensions and location of any worked-out caved areas It also allows analysis of changes in pillar stability as a result of mining progress from develop-ment to the extraction of coal pillars alongside a gob or between two gobs Mark and...

Pillar design in coal mines

May 06 2011 0183 32 pillar design in coal mines different pillar design approaches salmon versus sheorey formulae panel stability diffrent approaches local mine stiffness Fig Full Extraction Layout Traditional strength-based design methods using a factor of safety are not sufficient to eliminate the possibility of CPF in room-and-pillar min...

Pillar design

The following picture shows a typical post pillar layout Common sizes for post pillars are 4m x 4m or 5m x 5m with 12 m skin-to-skin Careful blasting is important otherwise blast-induced fracturing can significantly affect performance In very difficult ground post pillars may be designed as ribs with cross-cuts slashed later to produce...

Investigating the Width of Isolated Coal Pillars in Deep

the abutment pressure distribution in coal mines with extremely thick alluvium stratum Therefore a number of rockbursts have taken place resulting from the unreasonable width design of isolated coal pillar in deep min For instance a 80 m coal pillar in the 1300 and 1301 longwall working faces...

Applying Numerical Modelling to Pillar Design in South

Most layout designs in South African mines makes use of empirical pillar strength formulae such as those of Salamon and Munro 1967 and Madden 1987 for coal and Hedley and Grant 1972 in hard rock cas In general these formulae derive strength for failure of the pillar itself though whether by crushing of the centre of the pillar...

Typical Underground longwall coal mine development layout

Enjoy the videos and music you love upload original content and share it all with friends family and the world on YouTube...

EVALUATION OF UNDERGROUND COAL PILLAR DESIGN

21 Cross section of typical Bord and Pillar layout 6 22 The Tributary area pillar loading concept 9 23 The pressure arch theory 11 24 Concept of local stiffness and conditions for stable and unstable failure 13 25 Post-failure characteristics of sandwich yield pillars 14...

THE STABILITY ESTIMATION OF IRREGULAR COAL PILLARS

The compressive strength is 36Mpa From mining start in 1958 to the mining end in 1961 163000m2 total goaf area has been created and the pillar area is about 33206m2 pillar Coal pillar Collapsed boundary Fig1 Panel layout of room and pillar mining area account for 2037 of the total goaf area...

Probabilistic Approach to Coal Pillar Design Coal Age

Mar 21 2014 0183 32 Coal Pillar Design Like many other structural design problems coal pillar design can be expressed as a factor of safety Estimating stress on a coal pillar can be relatively straightforward but the method for determining coal pillar strength is not as well established The room-and-pillar layout was assumed to consist of 40-ft square...

Toward Pillar Design to Prevent Collapse of Room

underground miners Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress Factor of stability defined as local mine stiffness divided by post-failure pillar stiffness may offer a way to design room-and-pillar mines and eliminate collaps...