Rock Load Estimation in Development Galleries and Junctions for Underground Coal Mines: A CMRI-ISM Rock Mass Rating Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Avinash Paul ◽  
V. M. S. R. Murthy ◽  
Ajoy Kumar Singh
Keyword(s):  
Rock Mass ◽  
Support System ◽  
Coal Mines ◽  
Design Guidelines ◽  
Rock Mass Rating ◽  
Indian School ◽  
Indian Coal ◽  
Underground Coal Mines ◽  
Rock Load ◽  
Roof Rocks

Rock mass rating (RMR) plays important role in design and selection of support system (Ghosh, 2000). For stability assessment of rock mass it is very important to know the amount of rock load mobilized around the development gallery which is estimated using RMR (Singh et al., 2003, Barton et al., 1974, Bieniawski, 1984, and Ghosh et al., 1992). In Indian coal mines, Central Mining Research Institute-Indian School of Mines rock mass rating (herein after referred to as CMRI-ISM RMR) is mostly used for formulating design guidelines for supports. In this paper an attempt has been made to correlate CMRI-ISM RMR values and rock load of galleries and junctions for different gallery widths, ranging from 3.6 m to 4.8 m, at different densities of roof rocks. The proposed empirical expression can help in quick design of support system for underground coal mines working in the same regime.

scholarly journals Application of Foam Stopping for Mitigation of Spontaneous Heating In Underground Coal Mines

2019 ◽  
Vol 9 (2) ◽  
pp. 4425-4428
Keyword(s):  
Coal Mines ◽  
Proximate Analysis ◽  
Mine Planning ◽  
Inert Gases ◽  
Spontaneous Heating ◽  
Indian Coal ◽  
Planning And Design ◽  
Advanced Technologies ◽  
Underground Coal Mines ◽  
Valley Area

The problem of spontaneous heating is a major threat to safety and productivity in mines all over the world. In India, more than 80% of fires are caused due to Spontaneous Combustion. The applicability of inert gases is expensive, time-consuming and is a very tedious process. Hence the application of advanced technologies becomes essential to be introduced in mines. In this context, Central Mine Planning and Design Institute (CMPDI), Ranchi, India carried out an R&D project entitled “Construction of quick setting stopping in case of fire in an underground mine using expansion foam agent” under the funding from the Ministry of Coal, Government of India. Under this project, two Indian mines were selected in consultation with MCL for carrying out the proposed work in Orient Mine No.3 and Bundia Mine of MCL (Ib Valley AREA). Coals from both the mines have been collected and analysed in the laboratory. The proximate analysis and CPT/IPT results show that both the coals are moderately prone to spontaneous heating. Considering both intrinsic and extrinsic properties, two stoppings were constructed in the Hirakhand Bundia mines and four in orient mines. Periodic supervision along with the altering ingress of air from intake was been checked. After careful supervision of nearly 4 years, the stoppings proved to be strong enough to be leakage proof. This paper describes the application of foam technology as stopping to avoid air entry, thus preventing the occurrences of spontaneous heating/fire in a panel of Indian coal mines.

scholarly journals Experimental Study on Comprehensive Real-Time Methods to Determine Geological Condition of Rock Mass along the Boreholes while Drilling in Underground Coal Mines

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Ganggang Niu ◽  
Kai Zhang ◽  
Bosong Yu ◽  
Yanlong Chen ◽  
Yu Wu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Real Time ◽  
Coal Mines ◽  
Vibration Measurement ◽  
Geological Condition ◽  
Camera System ◽  
Underground Coal Mines ◽  
Measurement While Drilling ◽  
Borehole Camera ◽  
Rock Mass Condition

The geological condition is essential for mining design and disaster control in underground coal mines. The present research focuses on the real-time assessment method on rock mass condition during drilling boreholes. In situ comprehensive experiments were carried out using three methods, which are measurement while drilling (MWD) system, vibration measurement while drilling (VMWD) system, and borehole camera detecting system. In the MWD system, the operating parameters of the drilling machine were recorded, and a dimensionless index Id based on the collected parameters was adopted to assess the geological condition along the borehole. The results show that the state of rock mass can be well classified using the MWD system for both the cross-layer and in-seam boreholes. In the VMWD system, the vibration of the drilling bit was monitored, and the signal was analyzed in both time domain and frequency domain. The results indicate that the rock mass condition can be quantitatively evaluated using the mean square value of the signal and qualitatively estimated using the energy of the spectrum. In the borehole camera system, the photos of the rock mass along the borehole could be well captured, and the identified rock mass condition was used to verify the results of the MWD and VMWD systems. Comprehensive compassion between the results from the three systems shows that all the methods can give valuable information for the geological condition, and the outcomes of the different methods are generally comparable. For practical purposes, the advantages of the involved three detecting systems are discussed.

Estimation of Rock Load in Development Workings of Underground Coal Mines – A Modified RMR Approach

2018 ◽  
Vol 114 (10) ◽  
pp. 2167 ◽  
Author(s):  
Avinash Paul ◽  
Vemavarapu Mallika Sita Ramachandra Murthy ◽  
Amar Prakash ◽  
Ajoy Kumar Singh
Keyword(s):  
Coal Mines ◽  
Underground Coal Mines ◽  
Rock Load
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