The

maximum subsidence observed on the A-A and C-C profiles was approximately-80 mm (Fig.

Perhaps the most important subsidence relationship documented by the "SHE" work is the relationship between

Maximum subsidence, seam height, and the width and depth of the extraction area.

where k is the proportional coefficient, which can be back calculated with the maximum load and the

maximum subsidence of the voussoir beam.

Figure 3 shows the influence of Young's modulus on the settlement when c = 30 kPa, [psi] = 5[degrees], [phi] = 20[degrees], and [mu] = 0.2; Young's modulus is inversely proportional to the

maximum subsidence of the surface.

The

maximum subsidence was 35 mm, as shown in Figure 4.

Where these subsidences result over low extraction mines, the subsidence tends to be more sag-like, typically ranging in width from 500 to 1,000 feet and a

maximum subsidence of one to four feet.

Random scatter for subsidences determined on the NS and WE lines were matched in accordance with the results of the Kowalski (Kowalski, 2007) and Stoch (Stoch, 2005) studies as 2 % of

maximum subsidence for a given exploitation status (Table 2).

where [W.sup.0] = mq cos a is the

maximum subsidence during coal mining, m is the coal seam thickness, q is the subsidence coefficient, and [alpha] is the dip angle of the coal mining.

It describes the ratio of the

maximum subsidence [s.sub.max] to the average mining thickness g and is a dimensionless value that ranges from 0 to 1:

where x represents the coordinate in horizontal direction (m); y represents the coordinate of vertical direction (m); L represents the half width of the model (m); [omega](x, y) represents the subsidence at different heights of overlying strata (m); [[omega].sub.max](y) represents the

maximum subsidence at the same height (m); and C (y) is an undetermined coefficient.

Thus, the maximum observed uplift amounted to 60 mm and the

maximum subsidence to -40 mm.

In this stage, the

maximum subsidence value of point W9 was 8.5 mm, with a sinking speed of 0.142 mm/day.