An Experience of designing supports in newly opened Belgaon Underground coal mine

Belgaon block is located in the northern most ends of explored coal block of the eastern limb of Wardha Valley Coalfields (WVC). WVC is well known for its complexity like complex geological structures, strata control problems while dealing with thick coal seam, fire and water problem etc. The Belgon mine of SUNFLAG is however separated from Majra block in the south by a down throw fault. Designing of road ways and junction support in newly opened underground coal mine was a challenge due to its complex geology. To arrive at suitable support system, various experiments using cement as well as resin bolting were carried out. The pulls out tests were carried out on rock bolts grouted with cement as well as resin. The proposed paper deals with significance and importance of resin grout over cement and other issues related to strata control etc

Backfilling in sustainable development of underground mining

The backfill stability in underground stoping environment has a direct and large influence on the safety and economy of a mining stope, and finally, on the profitability of a mining operation. Its in-stability could lead to unsafe mining conditions within the mining stoping environment. In the present study, the backfill stability is studied due to the mining of adjacent stope through numerical modeling considering complex insitu rock mass and stress conditions. The study demonstrates how stable backfill acts as a good support measure in high in-situ stress conditions to improve mining stoping environment as well as it helps in waste management by means of putting waste rock in to the underground rather than on the surface thus saving our flora and fauna of our mother earth. Also, study signifies the importance of backfilling towards sustainable development of the underground hard rock mining

Fatigue properties of intact sandstone in pre-and-post failure and its implication to vibratory rock cutting

The pre- and post- failure fatigue properties of intact sandstone subjected to uni-axial cyclical loading in the laboratory is presented with its possible implication to vibratory rock cutting. The fatigue results subjected to sinusoidal, ramp and square waveforms at cyclic loading frequency of 5 Hz and peak amplitude of 0.05 mm is discussed herewith. It is observed that fatigue behaviour is a function of the dynamic energy of the load and the shape of the waveform. From the presented results, the practical significance of the behaviour of rock and rock masses within the excavation systems subjected to cyclic loads, especially in the vibratory rock cutting is put forward. To substantiate the cyclic breaking of rock under vibratory loading condition, a numerical simulation results using discrete element code is presented. Two loading cases were considered. In the first case, the wedge pick was loaded non-cyclically (monotonically), and in the second case it was loaded dynamically under cyclic sinusoidal loading at 50 Hz frequency. A load-deformation curve under monotonic (non-cyclic) loading condition and cyclic loading conditions were examined. The model showed a drop of about 25% in peak strength in the case of cyclically loaded wedge pick compared to monotonic or quasi-static loading of the wedge pick cutting. It is inferred that the vibratory loading has benefits in fracturing rock at relatively lower load compared to conventional loadin

Mining Engineering Curricula for 21st Century

In India, we hardly discuss the issues associated with our main mission: mining education. The subjects prevailing in professional discussions are R&D, technical papers and attending meetings. Here, an attempt has been made to present steps to salvage and bring renewed devotion to the teaching of mining Engineering course with special reform of the present Indian economic scenario

The Effect of Micro-Structure on Fatigue Behavior of Intact Sandstone

With advent of servo-controlled stiff testing machines, it is now possible to conduct tests on a rock in the laboratory under different variable controlled conditions. In this paper, cyclic fatigue behaviour of intact sandstone obtained from the rock burst prone coal mine in the Czech Republic were presented. Tests were conducted on MTS- 816 rock test system in the laboratory on intact rock samples of L/D ratio 2 under cyclic loading frequency of 0.1, 1, 3, 5, 7 and 10 Hz at amplitude of 0.1 mm under displacement control mode until failure of the samples in uni-axial compression. From, the primary results it was observed that at low loading frequency range of 0.1 to 3 Hz, there was degradation of the rock samples in terms of fatigue strength and modulus. While, at higher frequency rose-up in strength and deformation properties were observed. It was observed that the machine behaviour in terms of amplitude at higher loading frequencies might be affecting the results. It seemed that machine behaviour of servo-hydraulic testing system was also dependent on rock type under investigation

DYNAMIC PROPERTIES OF SANDSTONE ROCKSUBJECTED TO CYCLIC LOADING

The paper deals with a brief geological and historical introduction of Ostrava-Karvina coalfield (OKC), which is followed by details about the rocks tested; macroscopic and microscopic petro-graphic characterization, their physical and geophysical properties obtained from laboratory seismic measurement. The rock specimens used to test their geophysical properties were representative of all kinds of rock samples from borehole Darkov 265-01. To find out possible relations with geophysical and physical properties, and to discover the fatigue properties of the rock, all these rock specimens (37 in total) were tested under the same-identical dynamic cyclic loading conditions of 1 Hz frequency and 0.1 mm amplitude using ramp waveform. The findings and various relations obtained from laboratory investigations are reporte

An investigation into strength and porous properties of metamorphic rocks in the Himalayas: A case study

If a rock is porous in nature, the genetic complexity associated with its petrofabric makes it difficult to predict its behavior. Here, a comprehensive study of the porous nature, physical and geotechnical responses of three varieties of schist, i.e. quartz mica schist, quartz mica schist with quartz veins and biotite schist of low grade metamorphism obtained from Nathapa-Jhakri hydroelectric project site in the foot hills of Himalayas, India, has been presented. The porous nature of the schists has been brought out through the Mercury Intrusion Porosimetry (MIP) testing and strength behavior through uniaxial testing. Through an experimental invesigation, the porous nature and pore size distribution parameters from MIP, which are closely related to the strength and performance of metamorphic schistose rocks, have been studied. The significance of the porous nature and its response for consideration in the design is emphasized

Development in cable bolts and installation technique

Tendons and grouts for cable bolting must have high reliability remote capacity, the ability to withstand in adverse environmental conditions, and simplicity of operation. Hear, the current hardware and techniques available for cable bolting are illustrated vis-a-vis appropriate situations in which they should be applied. Besides its suitable application in various methods of thick seam coalmines as well as other methods are given

The Influence of Stoping Sequence and Various Rock Mechanics Parameters on Backfill Failure in Hard Rock Mining with Delayed Backfilling: The Review and Field Data Analysis Study

The profitability of a mining operation and the safety of the mining environment are of the utmost important in the present global competitive market. It is well known that backfill failure and or ore dilution has a direct influence on the cost of a mining operation in the case of underground hard rock mining with delayed backfilling. An overview of the various influencing parameters affecting backfill and ore dilution through the detailed review on the subject is presented in this paper. Also, a representative case study from a longhole blasting stoping environment is presented and discussed with. Through the review studies, it is found that different stope geometry parameters including planned stoping sequence have a direct influence on the ore dilution as well as the backfill stability. It is also emphasized through this study that dynamic strength consideration and effect of blast induced damage needs to be considered while designing the fill strength the fill strength. The studies presented in this paper demonstrate the role of the various discussed parameters in the above on backfill failure, thus resulting dilution of the economical ore as well as the stability problems. The illustrates the relationship between measured backfill overbreak, stope geometry and type, planned mining sequence as well as various other rock mechanics parameters etc

Characterization of failure modes and planned stabilization measures for the Ajanta caves in India

The Ajanta caves are classified as a UNESCO World-heritage monument, where ancient Buddhist rock-cut caves from the Second Century BC to 6th Century AD are found. The caves were carved manually in Basaltic rock mass in the Deccan trap basaltic flow of the Ajanta Formation of the Sahyadri Group in the Upper Cretaceous age. In the Ajanta caves, the hillside slopes are predominantly covered by surface boulders. Boulder dislocations caused by long-term rock mass deterioration, distressing, water percolation and weathering for a strike length of 600 m, and a height of 75 m; are a major concern when considering the safety of both visitors and site personnel, as well as with regard to the preservation of the historic UNESCO World Heritage site. This study was carried out to assess and characterize the formation of boulders with possible stabilization measures to be planned of a boulder field and slope surface is described and discussed herewith. The possible geological mode of development of the boulder field, rock mass characterization of slope, boulder stabilization philosophy is presented herewith along with planned various stabilization measures considering the esthetic value of the World Heritage site at Ajanta