longwall retreating

longwall retreating

[′lȯŋ‚wȯl ri′trēd·iŋ]
(mining engineering)
A longwall working system in which all the roadways are in the solid coal seam and the waste areas are left behind; developing headings are driven close to the boundary or limit, and the coal is taken out by the longwall retreating toward the shaft.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
As shown in Figures 5(i)--5(k), the upper hard roof, for instance, the fine sandstone which is strong enough to bear the overburden loads is called the key stratum [36], is not caving during the longwall retreating in Panel 1.
According to our study, the longwall retreating rate has a profound influence on roof loading.
Caption: Figure 2: Evolution of (a) final pressure and (b) time-weighted average pressure (TWAP) with longwall retreating time in Panel LW22306 of Bulianta mine.
Caption: Figure 4: Evolution of (a) the number of yielding, (b) yield pressure, and (c) average pressure drop during a supporting cycle with longwall retreating time in panel LW22306 of Bulianta mine.
Caption: Figure 5: Evolution of (a) periodic weighting interval, (b) periodic weighting intensity factor, (c) average TWASD during consecutive roof weightings, and (d) number of cycles experiencing roof weighting, with longwall retreating time in Panel LW22306 of Bulianta mine.
Caption: Figure 16: Loading degree of a shield-supporting cycle in different longwall retreating timings.