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Article

A Comparative Study of Various Empirical Methods to Estimate the Factor of Safety of Coal Pillars

1Department of Mining Engineering, Indian School of Mines – Dhanbad-04, Jharkhand, India


American Journal of Mining and Metallurgy. 2014, 2(1), 17-22
DOI: 10.12691/ajmm-2-1-3
Copyright © 2014 Science and Education Publishing

Cite this paper:
A. K. Verma. A Comparative Study of Various Empirical Methods to Estimate the Factor of Safety of Coal Pillars. American Journal of Mining and Metallurgy. 2014; 2(1):17-22. doi: 10.12691/ajmm-2-1-3.

Correspondence to: A.  K. Verma, Department of Mining Engineering, Indian School of Mines – Dhanbad-04, Jharkhand, India. Email: neurogeneticamit@gmail.com

Abstract

Design of coal pillars in a coal mine remains a challenge inspite of several theories proposed by several researchers over a period of time. India is heavily dependent on coal availability for supply of electricity to it’s billion of citizens. This has burdened the coal industry to increase the coal production which ultimately has lead to extraction of coal pillars also. Coal pillars are used to support the overlying roof rock to prevent it from falling. The dilemma with coal pillar stability is that On one hand, the size of the pillar should be as small as possible to enable maximum recovery of coal, while on the other hand, the pillar should be large enough to support the load of overlying strata. The stability of coal pillars has fascinated several researchers and hence many empirical equations have been proposed over the decades. In this paper, parameters like height of pillar, depth of pillar, compressive strength of coal, depth of the coal seam have been taken as input to estimate factor of safety of coal pillar from two mines i.e., Begonia and Bellampalli. It is found that Greenwald (1941), Salamon and Munro (1967), Sheorey (1992) and Maleki (1992) method has estimated failed cases correctly while Sheorey (1992) & Maleki (1992) have not predicted stable case of pillar correctly which is an interesting finding as empirical relations proposed by Sheorey (1992) is assumed to have good prediction in Indian condition.

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References

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Article

Stream Sediment Geochemical Survey of Gouap-Nkollo Prospect, Southern Cameroon: Implications for Gold and LREE Exploration

1Laboratory of Petrology and Structural Geology, University of Yaoundé I, Cameroon

2Department of Geology, HTTC, University of Bamenda, Cameroon

3Department of Geology, University of Dschang, Dschang, Cameroon

4Institut de Recherches Géologiques et Minières, Yaoundé, Cameroun


American Journal of Mining and Metallurgy. 2014, 2(1), 8-16
DOI: 10.12691/ajmm-2-1-2
Copyright © 2014 Science and Education Publishing

Cite this paper:
Soh Tamehe Landry, Ganno Sylvestre, Kouankap Nono Gus Djibril, Ngnotue Timoleon, Kankeu Boniface, Nzenti Jean Paul. Stream Sediment Geochemical Survey of Gouap-Nkollo Prospect, Southern Cameroon: Implications for Gold and LREE Exploration. American Journal of Mining and Metallurgy. 2014; 2(1):8-16. doi: 10.12691/ajmm-2-1-2.

Correspondence to: Ganno  Sylvestre, Laboratory of Petrology and Structural Geology, University of Yaoundé I, Cameroon. Email: sganno@uy1.uninet.cm; sganno2000@yahoo.fr

Abstract

Stream sediments play a significant role in geochemistry exploration by identifying possible sources of anomalous element concentration. This work is the baseline stream sediments geochemical study which brings general information on the geochemical dispersion of the metal elements (especially gold) at Gouap-Nkollo prospect (SW Cameroon) with the aim of providing a useful guide for future exploration strategies. For this study a concentration of 47 elements was measured in 10 stream sediment samples using BLEG and ICP-MS methods, but emphasis was given to the following 21 chemical elements: Al, Ca, Fe, K, Mg, Na, P Ag, Au, B, Co, Cr, Cu, Mn, Ni, Ti, Zn, Ce, La Th, U and Zr. Averaged elemental concentration for each samples obtained by statistical analysis showing patterns of enrichment and depletion which may relate to localized mineralization conditions or local lithological changes. Results showed that the stream sediments have high concentrations of Au, Ce and La with average values of 314.85ppm, 19081ppm and 11808ppm respectively for gold, cerium and lanthanum. Cerium and Lanthanum have considerably high concentrations when compared with other Rare Earth Elements (REE) analyzed. These concentrations represent interesting indices for Au and LREE mineralization’s. The geochemical dispersion of the metal elements (especially gold) reveals that high concentrations are recorded in the northern part of the prospect, close to the quartz-tourmaline vein within the quartzite. This result indicates that the Au and other metal elements probably originated from the quartz-tourmaline veins hosted by surrounding rocks. Detailed exploration work including geochemical soil sampling and geophysical survey is highly recommended in the northern part of the Gouap-Nkollo prospect, where anomalous concentrations of Au were observed, for further investigation.

Keywords

References

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Article

Optimisation of Dump Slope Geometry Vis-à-vis Flyash Utilisation Using Numerical Simulation

1Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai, India

2Mine Fire Division, CSIR-Central Institute of Mine and Fuel Research, Dhanbad, India


American Journal of Mining and Metallurgy. 2014, 2(1), 1-7
DOI: 10.12691/ajmm-2-1-1
Copyright © 2014 Science and Education Publishing

Cite this paper:
S.P. Pradhan, V. Vishal, T. N. Singh, V.K. Singh. Optimisation of Dump Slope Geometry Vis-à-vis Flyash Utilisation Using Numerical Simulation. American Journal of Mining and Metallurgy. 2014; 2(1):1-7. doi: 10.12691/ajmm-2-1-1.

Correspondence to: S.P.  Pradhan, Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai, India. Email: saradaiitb@gmail.com

Abstract

Stability of waste dump is now gaining importance due to increasing depth and size of mine. Management of dump nearby mining areas is one of the most critical and crucial task for mine management due to limited land and other governing laws related to environment and forest conservation. In this paper, a study was conducted to establish the effect of slope angle on the stability of waste dump for accommodation of flyash is carried out. Based on numerical simulation, it was found that the dump slope of 60 m height with 36° slope can be critically stable with 20% flyash randomly mixed with overburden materials whereas flatter slopes provide higher factor of safety. Keeping other parameters constant, the optimum slope of 32° is the best possible to accommodate the mine dump for its long term stability. These findings were further supported by study of maximum velocity vectors and shear strain rates in every case and the extent of damage zone due to tensile pull. It is hoped that this technical note will find utility wherever a design of dump of chosen material type is being planned where the wastes can be managed alongside ulitisation of flyash.

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References

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