International Journal of Mining and Mineral Engineering (6 papers in press)
Determining factors of investment in mineral exploration
by Anwar Yarin, Ronal Estrella, Walter Sánchez, Carlos Miranda
Abstract: The objective of this study was to identify the critical factors that favor attracting a greater investment in mineral exploration. A research methodology was used that involved the exhaustive analysis of data obtained from public databases on various countries, as well as different qualitative and quantitative techniques. This study uses a new proxy variable to quantify geological potential: mining production value. Likewise, we include another new variable, land area/population. It is concluded that investment not only depends on geological potential and investment climate, but is also influenced by population density. The greater the geological potential and investment climate, the higher investment in mineral exploration will be. Meanwhile, high population density leads to the opposite effect. Future studies should consider other variables or even new formulations to more robustly explain the competitiveness of countries to appear attractive to mineral investments.
Keywords: Investment factors; investment in exploration; mineral exploration; geological potential; mineral investments; mining production; economic freedom; mining reserves; investment climate; metals and mining; economic model.
DESIGN OF PANEL AND SUPPORT SYSTEM FOR EXTRACTION OF INCLINED THICK COAL SEAM USING NUMERICAL MODELLING
by Sreenivasa Rao Islavath, Sujeet Bharti
Abstract: The bord and pillar method is an efficient technique proven for mining of inclined coal seams in the Indian coal mining scenario. Among two stages of workings namely development and depillaring, depillaring operation will develop the high stress concentration on the workings and will pose many strata control issues such as roof convergence, floor heaving, side spalling and pillar/ribs crushing. A detailed stability analysis need to be conducted to control these strata issues and estimate the optimum size of the panel consist of pillars, ribs, slices and other roadways and also support system. In this paper, the stability analysis of the panel and design of the support system are presented for safe winning of inclined coal seam no. 1 of SRP 3 & 3A mine, SCCL using 2D and 3D numerical modelling approach. The coal seam/panel is developed by rhombus pillars of 25 m x 25 m size with 4.2 m and 4.8 m wide galleries and these pillars are being proposed for depillaring. A total of nineteen 3D numerical models are developed for analysing the development of stresses during depillaring operation in sixteen stages and eight 2D numerical models are developed to determine the conditions of pillars, ribs and roadways and also this study suggests the suitable pillar size, gallery width, mining height and the support system for safe working of the coal seam.
Keywords: Depillaring; Numerical modelling; Safety factor; Displacement; Support.
Application of Artificial Intelligence Techniques for identifying Rock Mass Quality in an Underground Tunnel.
by Sylvanus Sebbeh-Newton, Hareyani Zabidi
Abstract: The paper examined how efficient the penetration rate recorded from a horizontal probe drilling could be integrated with rock properties to predict Rock Mass Rating (RMR) in underground tunnels. The estimation of RMR involves the use of intact rock strength which is usually expensive and time consuming. Penetration rate is automatically obtained from rock drilling and excavations but has been under-utilized in tunnel construction. The horizontal Probe drilling dataset from the Pahang-Selangor Raw Water Transfer Tunnel (PSRWT) project was used to develop intelligence models that could be used to identify the rock mass quality ahead of the excavation. In this study, two common artificial intelligence techniques; Artificial Neural Network (ANN) and Adaptive Neuro-fuzzy Inference System (ANFIS) were used to achieve this aim. The input variables include rock quality designation (RQD), discontinuity spacing (DS), Groundwater inflow (GW), discontinuity conditions (DC) and penetration rate (PR). The target variable in the case study was rock mass rating index. Coefficient of determination (R2), root mean squared error (RMSE), and variance accounted for (VAF) were calculated to assess the developed models. The R2, VAF, and RMSE values of 0.922, 92.08 %, and 2.284 respectively for ANN indicates a lower prediction output than the ANFIS model with R2, VAF, and RMSE values of 0.925, 92.27 %, and 2.054 respectively. The results show that ANFIS generally outperformed ANN in predicting rock mass rating.
Keywords: Artificial Neural Network (ANN); Adaptive Neuro-Fuzzy Inference System (ANFIS); Penetration Rate; Rock Mass Rating system; Tunneling.
Demonstration of a technical system for water disaster prevention and control when mining under sandstone aquifers
by Li Jianghua, Li Hongjie, Lian Yuguang, Luo Yaqi
Abstract: A heterogeneous sandstone aquifer (K8) lying above a No. 3 coal seam greatly threatens the safety of mining operations at working faces in the Zhao Coal Mine. This study demonstrated a disaster prevention approach involving the transient electromagnetic method and drainage drillings into the water-rich areas before mining, and evaluated the drainage effect. The research followed three steps: (1) three water-rich areas were identified in the sandstone aquifer K8; (2) in the water-rich areas, three drilling sites were designed, and ten holes were drilled; (3) water outflow from the drilling holes decreased obviously over time, and the water-rich areas almost disappeared following water drainage. The total volume of drained water was more than the predicted value; hence, the approach met the requirements for water drainage. This technical system of water disaster prevention and control was proposed for circumstances of mining under roof aquifers, which included geophysical prospecting, drilling exploration, water drainage, and effect evaluation.
Keywords: sandstone aquifer; transient electromagnetic method; water-rich area; drilling exploration; drainage water; effect evaluation.
Experimental study on the influence of moisture content on soft coal strength characteristics
by Chen Wang, Yuwen Gao, Chenye Guo, Kun Wei
Abstract: The strength characteristics of soft coal are influenced by moisture content. The 8# seam is soft in panel II 883-1. The panel II 883-1 is a top slice fully mechanized mining working face. With the increase of moisture content in the experimental range, the following conclusions are obtained: (1) Uniaxial compressive strength and elastic modulus of coal samples decrease gradually; (2) Peak strain and maximum axial strain increase and reach stable at 4% and 5% respectively; (3) When shear angles are respectively 45
Keywords: Moisture content; Strength characteristics; Soft coal; Uniaxial compression; Shear tests with variable angles.
SONAR MAPPING OF ABANDONED WATER-LOGGED UNDERGROUND COAL MINE AND BACKFILLING OPERATION USING UNDERWATER CAMERA
by Samir Kumar Pal, Anup Kumar Tripathi, Susmita Panda, Sathish Kumar Palaniappan
Abstract: The paper describes mine mapping and backfilling work carried out during field experimentations on simple hydraulic gravity blind backfilling method for the stabilization of ground above old abandoned waterlogged underground coal mine of Eastern Coalfields Limited (ECL), India. The section of the abandoned mine to be backfilled was explored using the underwater remote operated vehicle (ROV) camera before actual backfilling work. The use of sonar imaging facility of the ROV camera for mapping of the underground waterlogged area to be backfilled is described. The plotting of gradual progress of sand bed as the filling progressed in different stages through different boreholes as monitored from surrounding camera boreholes is also described.
Keywords: Bord and Pillar mining; surface subsidence; coal pillar deterioration; hydraulic gravity blind backfilling; movable backfilling laboratory; computerized data acquisition; underwater camera; sonar imaging; filled area monitoring; mine mapping.