Stowing Advantages & Hand Packing

The main advantage of stowing is that goaf is packed solidly and the strata over the goaf are supported. 

The advantages resulting from this are:

1) There are no chances of gas accumulation in the goaf in coal mines.

2) Leakage of ventilating air is eliminated.

3) Roadways and working places are rendered safe.

4) Better roof control results and effects of surface subsidence are minimised. Very often, there is no subsidence.

5) High extraction percentage is attained. It makes possible the extraction of a thick seam, a seam below fire area, below water bearing strata and below railways, rivers, towns, etc. Panel barriers also can be extracted and wastage of coal underground is reduced.

6) Full extraction (nearly 9"5%) is possible in a seam thicker than 4.5 m only in conjunction with stowing.

7) Depillaring of contiguous seams in any order is rendered possible.

8) No danger of inundation during depillaring.

Sand packing is adopted to stabilise pillars and workings where pillars are small and galleries are high or wide. It is adopted sometimes to form a barrier underground against fire area.

Hand Packing

Hand packing is simple and does not involve capital cost but is limited in scope and depends on human factor for efficiency. It can advantageously be used in places where hydraulic stowing is not much effective, as in flat and shallow seams. Tubs can be conveniently handled any where in flat seams and this facilitates hand packing. It is also useful in seams steeper than 25⁰ when arrangements can be made to tip the tipping tubs and the material packs' itself. The process is slow and heavy on manpower; the most efficient operation gives-an average of 10 m³ per man shift when materials are close at hand.