skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Shield support selection based on geometric characteristics of coal seam

Abstract

The most initial investment in longwall face equipping is the cost of powered support. Selection of proper shields for powered supports is based on load, geometric characterization of coal seams and economical considerations.

Authors:
; ;  [1]
  1. Tarbiat Modarres University, Tehran (Iran). Faculty of Engineering, Mining Engineering Group
Publication Date:
OSTI Identifier:
20781512
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Mining Science (English Translation); Journal Volume: 42; Journal Issue: 2; Other Information: goshtasb@modares.ac.ir
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; COAL SEAMS; POWERED SUPPORTS; SHIELD SUPPORTS; ECONOMICS; THICKNESS; INCLINATION; GEOMETRY

Citation Formats

K. Goshtasbi, K. Oraee, and F. Khakpour-yeganeh. Shield support selection based on geometric characteristics of coal seam. United States: N. p., 2006. Web. doi:10.1007/s10913-006-0042-7.
K. Goshtasbi, K. Oraee, & F. Khakpour-yeganeh. Shield support selection based on geometric characteristics of coal seam. United States. doi:10.1007/s10913-006-0042-7.
K. Goshtasbi, K. Oraee, and F. Khakpour-yeganeh. Sun . "Shield support selection based on geometric characteristics of coal seam". United States. doi:10.1007/s10913-006-0042-7.
@article{osti_20781512,
title = {Shield support selection based on geometric characteristics of coal seam},
author = {K. Goshtasbi and K. Oraee and F. Khakpour-yeganeh},
abstractNote = {The most initial investment in longwall face equipping is the cost of powered support. Selection of proper shields for powered supports is based on load, geometric characterization of coal seams and economical considerations.},
doi = {10.1007/s10913-006-0042-7},
journal = {Journal of Mining Science (English Translation)},
number = 2,
volume = 42,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • The search for a more effective means of coping with methane liberation has resulted in the expanded use of seam degasification. Its advantages are measured not only in reducing the hazards due to methane, but also in producing a marketable commodity, the gas itself. However, the success of a methane drainage system is the culmination of many complex factors, the most important being the coal seam permeability. The two most popular drainage techniques used in mining today are the vertically stimulated borehole method and the in-seam horizontal borehole method. The objective of this paper is to determine the permeability rangemore » in which the selection of the degasification technique is based primarily on equipment and economic analysis. A discussion of the equipment involved is incorporated into examples evaluated by the Pennsylvania State University coal methane simulation model.« less
  • Over the past few years, while investigating the types of fracture treatments conducted in coal, the authors have categorized five separate stimulation scenarios. These scenarios are described as follows: A shallow coal seam where a horizontal fracture will be created. A series of thin coal seams in a depth range where single, planar vertical fractures will be created. A single thick coal seam where the hydraulic fracture will be confined entirely in the coal and complex fracture system (multivertical or T-shaped fractures) created. An hydraulic fracture where the fracture is initially contained within a single coal seam, but during themore » latter portion of the treatment the fracture begins to propagate vertically into the bounding layers. A high-permeability (highly cleated-fractured) coal seam that does not require stimulation.« less
  • Purpose: To determine required PTV margins for ≤1% loss in mean population TCP using systematic (Σ) and random (σ) errors calculated from daily cone-beam CT (CBCT) images of head and neck patients. Methods: Daily CBCT images were acquired for 50 head and neck patients. The CBCT image sets acquired at each fraction were registered with planning CT to obtain positional errors for each patient for each fraction. Systematic and random errors were calculated from data collected for 50 patients as described in IPEM On Target report. CTV delineation uncertainty of 2mm is added quadratically to systematic error. Assuming a sphericalmore » target volume, the dose in each voxel of target volume is summed for each fraction in the treatment by shifting the dose grid to calculate mean population TCP inclusive of geometric uncertainties using a Monte Carlo method. These simulations were repeated for the set of Σ and σ in each axis for different PTV margins and drop in TCP for each margin are obtained. In order to study the effect of dose-response curve on PTV margins, two different σα of 0.048 Gy-1 and 0.218 Gy-1 representing steep and shallow dose-response curves are studied. Σ were 2.5, 2.5, 2.1 mm and σ were 0.3, 0.3 0.2 mm respectively in x, y and z axis respectively. Results: PTV margins based on tumor radiobiological characteristics are 4.8, 4.8 and 4 mm in x, y and z axis assuming 25 treatment fractions for σα 0.048 Gy-1 (steep) and 4.2,4.2 and 2.2 for σα of 0.218 Gy-1 (shallow). While the TCP-based margins did not differ much in x and y axis, it is considerably smaller in z axis for shallow DRC. Conclusion: TCP based margins are substantially smaller than physical dose-based margin recipes. This study also demonstrates the importance of considering tumor radiobiological characteristics while deriving margins.« less
  • Phononic crystals (PnCs) and n-type doped silicon technique have been widely employed in silicon-based MEMS resonators to obtain high quality factor (Q) as well as temperature-induced frequency stability. For the PnCs, their band gaps play an important role in the acoustic wave propagation. Also, the temperature and dopant doped into silicon can cause the change in its material properties such as elastic constants, Young’s modulus. Therefore, in order to design the simultaneous high Q and frequency stability silicon-based MEMS resonators by two these techniques, a careful design should study effects of temperature and dopant on the band gap characteristics tomore » examine the acoustic wave propagation in the PnC. Based on these, this paper presents (1) a proposed silicon-based PnC strip structure for support tether applications in low frequency silicon-based MEMS resonators, (2) influences of temperature and dopant on band gap characteristics of the PnC strips. The simulation results show that the largest band gap can achieve up to 33.56 at 57.59 MHz and increase 1280.13 % (also increase 131.89 % for ratio of the widest gaps) compared with the counterpart without hole. The band gap properties of the PnC strips is insignificantly effected by temperature and electron doping concentration. Also, the quality factor of two designed length extensional mode MEMS resonators with proposed PnC strip based support tethers is up to 1084.59% and 43846.36% over the same resonators with PnC strip without hole and circled corners, respectively. This theoretical study uses the finite element analysis in COMSOL Multiphysics and MATLAB softwares as simulation tools. This findings provides a background in combination of PnC and dopant techniques for high performance silicon-based MEMS resonators as well as PnC-based MEMS devices.« less