Compressibility of materials and backfilling mixtures with addition of solid wastes from flue-gas treatment and fly ashes

Skrzypkowski, Krzysztof

doi:10.1051/e3sconf/20187100007

Cited by 21 publications

(15 citation statements)

References 10 publications

(8 reference statements)

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“…In the same way, as the second phase of the technology, similar perpendicular excavations are constructed. Finally, between the intersecting excavations, some parts of the orebodies are left in their original location, forming pillars [21]. Their role is to support overlying rocks and secure their stability and work safety for miners.…”

Section: Room and Pillar Methods In Hard Rock Miningmentioning

confidence: 99%

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

et al. 2019

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This paper presents the results of laboratory tensile testing of segmentally-installed glue-in roof bolting. We studied roof bolting of the type Olkusz-16A (Boltech Sp. z o.o., ZGH Bolesław S.A., Bukowno, Poland), additionally equipped with a steel rod coil, which was mounted in steel cylinders filled with a concrete mixture using multi-part resin cartridges with a diameter of 0.024 m and length of 0.045 m. The mounting depths were 0.1 m and 0.2 m, respectively. Our main purpose was to determine the effect of the bolt hole diameter, which assumed the values 0.028 m, 0.032 m, 0.035 m, and 0.037 m, respectively, on the load-bearing capacity of the roof bolting in relation to the mounting depth. We found that the mounting depth of 0.2 m was sufficient for the roof bolting to exhibit its full load and displacement properties for all four diameters of the bolt hole. To determine whether the roof bolting was capable of transferring the load in situ, we presented the results of the predicted load on the roof bolting applied in a room and pillar mining method in an underground mine of zinc and lead ore deposits. Our objective was to determine the influence of the room and pillar mining method geometry on the range of the fault zone of rocks around pits. We designed the deposit excavation model using the Examine3D numerical modeling software, which is based on the boundary element method. We created three-dimensional models for three variants of working space opening widths: featuring two, three, and four rows of rooms. The geometry of rooms and pillars corresponded to the mine conditions; the width, height, and length parameters were all 5 m. We determined the strength, strain, and structural parameters of the rock mass on the basis of laboratory studies of the drill core and rock forms collected from the room longwall. We used the strength factor to specify the maximum range of the fault zone of rocks around pits. In the last stage of research, we compared the load value obtained based on numerical testing with the maximum load obtained in the tensile strength tests of the roof bolting and determined the safety factor of the segmentally-installed roof bolting.

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Section: Room and Pillar Methods In Hard Rock Miningmentioning

confidence: 99%

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

et al. 2019

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“…The mine uses two methods of exploitations: room and pillar and shortwall. The post-mining area is liquidated by application hydraulic backfilling [8,9]. Exploitation fields with a length of 100 m are divided into haulage rooms and within operating pillars up to 30 m. So separated pillars are selected with rooms usually 5-6 m wide, and 5-6 m high, driving parallel to the front line.…”

Section: Room and Pillar Methods For Thick Ore Deposit In The Zinc Andmentioning

confidence: 99%

The Influence of Room and Pillar Method Geometry on the Deposit Utilization Rate and Rock Bolt Load

Skrzypkowski

2019

Energies

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In this article, a model of ore deposit in form of a lense carried out in the MineScape program, is presented. The lense had a thickness of 30 m, length along the strike 200 m, and the depth buried was for 80 m to 110 m below the surface. In the first layer, counting from the lowest level, a room and pillar method with variable geometry was designed. The width and length dimensions for rooms and pillars were: 4 m, 5 m and 6 m, respectively. For the selected part of the deposit, three variants of the system with variable geometry of rooms and pillars were designed, for which the deposit utilization coefficient was determined. The next stage of the research was to determine the influence of the geometry of the pillars and rooms on the range of the rock destruction zone around room excavations. For this purpose, numerical calculations using the three-dimensional Examine 3D program, based on the boundary element method, were made. The results of numerical tests were used to calculate the load of the rock bolt support, which is currently used in the zinc and lead underground mine "Olkusz-Pomorzany" in Poland. Currently in the mine, the bolt spacing is 1 m × 1 m, and the technology for fixing the bolt rod is based on resin cartridges that completely fill the bolt hole. In order to spread the spacing of the rock bolt support and to apply segmental fixing of the bolt rod, in the laboratory tests, rock bolt supports with increased strength were tested. Based on the results obtained, it was found that the rock bolt can be installed segmentally, using a cement grout, and its spacing can be increased to 2 m.

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“…Therefore, aeolian sand is an ideal paste-backfilling material. Furthermore, power plants near the mine can provide fly ash, which can also be used as a paste-backfilling material [28][29][30]. With comprehensive consideration of the backfilling costs, quality, and other factors involved in CPB, the materials to be prepared for this mine's paste-backfilled structure are determined as aeolian sand, power plant fly ash, cement, and quicklime.…”

Section: Selection Of Paste-backfilling Materialsmentioning

confidence: 99%

Stability Analysis of Surrounding Rock in Paste Backfill Recovery of Residual Room Pillars

et al. 2019

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A method of paste backfill recovery for residual room coal pillars is hereby proposed. The principles and processes of this method are systemically explained to address issues such as mining-induced earthquakes from spontaneous destabilization, surface subsidence, and low recovery rates. These are caused by the instability of residual coal pillars due to their spontaneous combustion in room-and-pillar mining in medium-to-small coalmines in the northern Shaanxi area. This method is based on the local abundance of surface aeolian sand and solid wastes to be used as paste-backfilling materials in coalmines in the northern Shaanxi area. Uniaxial compressive strength, bleeding rate, and slump tests were performed on paste-backfilled samples constituted at different ratios based on the types of materials involved in paste backfilling in the northern Shaanxi region, thereby helping to confirm the optimal ratios for paste-backfilling materials for the Ershike coal mine. A simulation was conducted to investigate the failure, goaf vertical stress distribution, and surface deformation properties of paste-backfilled pillars and coal pillars, where paste backfilling was used with paste-backfilling materials constituted at different compressive strengths. This was to verify the experimental results that would be obtained with paste-backfilling materials constituted at different ratios, and reveal the mechanism by which paste backfilling of residual room pillars can maintain the mine's surrounding rock stability. These study results are of great instructive significance to the safe recovery of residual room pillars in China's western mining areas.Sustainability 2019, 11, 478 2 of 13 leading to severe mining catastrophes such as large-area roof collapses, and even mining-induced earthquakes. Therefore, the problem of how to recover residual room pillar resources safely has become a major issue [8][9][10].Considerable research has been undertaken by scholars in China and other countries regarding the recovery of residual room mining pillar resources. Singh et al. [11] carried out an analysis of the state of coal pillar recovery in India, studying the impact factors on the stability of deep-seated room-and-pillar mine pillars under the condition of high stress; Gan et al. [6] examined the prudent allocation of mining gateways underneath room-and-pillar goafs; Ghasemi et al. [5] proposed a new coal pillar design method to reduce support stress concentration and coal pillar sizes; Haibo et al. [12] studied roof stress on room mining residual pillars and analyzed the critical factors influencing roof stability; Jixiong et al. [13,14] analyzed the impact pattern of compression ratio on coal pillar stability, establishing a mechanical model for solid-filled recovery room pillars, and designed a corresponding coal pillar recovery process; Yun et al. [14] investigated the safe recovery of residual room pillars below an aquifer, proposed a method of short wall block mining, and established a water-conducting fracture zone development heig...

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Compressibility of materials and backfilling mixtures with addition of solid wastes from flue-gas treatment and fly ashes

Cited by 21 publications

References 10 publications

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

The Influence of Room and Pillar Method Geometry on the Deposit Utilization Rate and Rock Bolt Load

Stability Analysis of Surrounding Rock in Paste Backfill Recovery of Residual Room Pillars

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