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Monday, August 10, 2020 | History

1 edition of Effects of a retreating longwall on a three-entry gate road system found in the catalog.

Effects of a retreating longwall on a three-entry gate road system

Effects of a retreating longwall on a three-entry gate road system

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Published by U.S. Dept. of the Interior, Bureau of Mines in Pittsburgh, Pa. (P.O. Box 18070, Pittsburgh 15236) .
Written in English

    Subjects:
  • Longwall mining.,
  • Pillaring (Mining),
  • Mine roof bolting.,
  • Gate roads (Mining)

  • Edition Notes

    Bibliography: p. 18-19.

    Statementby Richard A. Allwes ... [et al.].
    SeriesReport of investigations / United States Department of the Interior, Bureau of Mines ;, 8996, Report of investigations (United States. Bureau of Mines) ;, 8996.
    ContributionsAllwes, Richard A.
    Classifications
    LC ClassificationsTN23 .U43 no. 8996, TN275 .U43 no. 8996
    The Physical Object
    Paginationii, 19 p. :
    Number of Pages19
    ID Numbers
    Open LibraryOL2663184M
    LC Control Number85600224

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Effects of a retreating longwall on a three-entry gate road system Download PDF EPUB FB2

Additional Physical Format: Online version: Effects of a retreating longwall on a three-entry gate road system. Pittsburgh, Pa. (P.O. BoxPittsburgh ):. Support loading and strata activity were monitored to determine the effects of retreat longwall mining on the gate road ground control system.

Analyses of pillar stress and roof bolt loading histories revealed that headgate roof support elements experienced cumulative loading throughout the life of the longwall panel. ri / the effects of a retreating longwall on a three-entry gate road system, pb, $ 25 ri / utilization of simulated coal gases for reducing iron oxide pellets, pb, $ 8 ri / hydrochloric acid-oxygen leaching and metal recovery from a copper-nickel bulk sulfide concentrate, pb, $ 12 Advancing and Retreating Longwalls.

Comparison of Advancing and Retreating Longwalls. The advantages of retreating longwalls compared toadvancing are: Gate road formation isremote from face operations (less congestion at face ends, less supplies intolongwall face area, face not held up waiting for gate road preparation or viceversa, no problems of dust production from gate road.

Thus, the design of any underground opening must consider roof/pillar and floor as one structural system. This paper presents guidelines for the design of mine floors, including the necessary field and laboratory investigations and the determination of the bearing capacity of floor by: The census also shows that 46 pct of the operators use a three-entry gate road, 38 pct use a four-entry gate road, and the remaining 16 pct use other configurations or were unknown.

Based on these figures and to narrow the extent of the investigation, a three-entry gate road using by ft pillars was selected for study. Main roof fall, local fall and induced roof wall, floor heaving, precautions during main fall and surface subsidence.

UNIT III EXTRACTION AND TRANSPORT ON A LONGWALL FACE 10 Methods of mining coal on longwall faces, machines – shearers, ploughs etc., methods of cutting and face advancement, stables and sumping, gate road pillar extension.

Basic longwall mining principle simplified (retreating longwall in this case) A coal haulage system is installed across the face, on modern faces an "armoured face conveyor or AFC". The roadways which form the sides of the block are referred to as "gate roads".

Longwall mining has traditionally been a manual process in which alignment of the face equipment was done with string lines.

Technologies have been developed which automates several aspects of the longwall mining operation, including a system that aligns the face of the retreating longwall panel perpendicularly to the gate-roads. In Figurethe gate roads are protected by a pack wall against the gob.

Pipelines are laid through the pack wall to reach nearly the center line of the gob, then manifolded to a larger diameter pipe in the gate road. In Figurethe partially stowed longwall gob, cavities are purposely left between alternate packs.

The overlying strata Cited by: 7. The majority of in seam drilling is done from stubs driven in to the future longwall block from the virgin side gate road. The holes are drilled in a fan pattern with holes ranging from metres to metres in length.

The objective of these holes is to drain both the longwall block and the next gate road development panel. Where. This US Bureau of Mines report describes the results from an in-mine investigation of an alternative longwall gate road design.

The coal mine operator modified the pillar layout (reversed the location of the big and small pillars) in a portion of a three-entry longwall gate road area. However, the retreating longwall provides first-hand information about geological conditions along the entire length and width of the panel, which is very important if adverse geological conditions are discovered, such as faults, rolls, or pinch-outs, etc.

Entry maintenance is easier and lasts longer in the retreating longwall since the entries. Chekan's 15 research works with 57 citations and reads, including: Impact of air velocity and support advance on shield-generated dust. J.M. Listak's 17 research works with citations and 3, reads, including: Silica and respirable content in rock dust sample.

The entries were represented by a single grid rather than a detailed gridding for each gate road at the tailgate and headgate sides to simplify these underground transport and ventilation airflow pathways. Thus, single grid entries represent the combined effects of the three-entry by: For readers interested in the history of longwall mining and greater detail on recent developments affecting longwall mining, the report includes a bibliography.

Content: Front Matter • List of Tables • List of Figures • Executive Summary • Preface • Table of Contents • 1. Introduction 2. A Description and History of Longwall Mining 3. The longwall "panel" (the block of coal that is being mined) is typically km long and mm longwall shearer is a sophisticated machine with a rotating cutting drum that moves mechanically back-and-forth across the coal seam in the panel.

NASA Images Solar System Collection Ames Research Center. Brooklyn Museum. Full text of "Mechanized Longwall Mining, a Review Emphasizing Foreign Technology". Coal and gas outbursts are serious safety concerns in the Chinese coal industry. Mining of the upper or lower protective coal seams has been widely used to minimize this problem.

This paper presents new findings from longwall mining-induced fractures, stress distribution changes in roof strata, strata movement and gas flow dynamics after the lower protective coal seam is extracted in a deep Cited by: 7. Abstract. Longwall developments in the UK have historically consisted of single entry gate roads.

Adjacent developments were separated from existing pales by large barrier pillars (designed of sufficient width to get away from the longwall abutments of the previous panel) or by small barriers driven in the shadow, or de-stressed zone, of the previous panel.longwall retreating.

A system of longwall working in which the developing headings are driven narrow to the boundary or limit line and then the coal seam is extracted by longwall faces retreating toward the shaft. In this method, all the roadways are in the solid coal seam and the waste areas are left behind.Longwall mining.

See also what's at Wikipedia, your library, or elsewhere. Broader term: Coal mines and mining; Used for: Mining, Longwall; Longwall method of mining; Filed under: Longwall mining Longwall gate road roof instability and methods of control in the lower Kittanning Coalbed of Central Pennsylvania /, by Eric R.

Bauer, E. D. Krupa, and Jeffrey M. Listak (page images at HathiTrust).