NORTHERN EXTENDED COLLIERY. 259 



Northern Extended Colliery. 



This is one of the collieries belonging to the estate of the 

 late Mr. Andrew Sneddon, and is under the management of 

 Mr. D. Sneddon. It is situated near the Teralba railway 

 station. The Great Northern seam is being worked, which 

 is 15ft. thick; of this 12ft. Gin. is good marketable coal. At 

 present they take out 7ft. Gin. of the centre coal. About 

 2ft. Gin. of bottom coal is inferior, so it is left in position. The 

 top coal is also left till later on, as it is awkward to mine, being 

 so high; besides, it helps to support the pillars, which are 

 thus made relatively shorter. The seam is subject to swal- 

 lows or depressions. These are fairly shallow, but the coal 

 and included bands, also the roof and floor, are affected, which 

 points to the irregularities having been caused subsequently 

 to the formation of the coal, for otherwise the coal would 

 have filled up the depressions in horizontal layers. The roof 

 is conglomerate, and the floor a fine-grained sandstone. 



The workings are reached by a tunnel or main dip. Eight 

 or ten skips in a set are hauled up the roadways by direct 

 haulage. A drag-bar shaped like a Y (Fig. 165) is 



Fig. 1G5. Dragbar. 



hooked on to the back axle of the last full skip. The hooks 

 on each branch are double, so when the point of it lie bar 

 digs into the ground, it is not likely to become detached. 

 This bar drags behind on the ground, but in case of a break- 

 away, it sticks in the floor and overthrows the skip, thus avoid- 

 ing a worse accident. Where the road goes to the rise a jig 

 is used, the full skips as they descend drawing up the empties. 

 In this instance, also, 8 to 10 skips go to make up a set. At 

 the upper end of the jig, the pulley round which the rope 

 passes, as also the band brake, are arranged in a frame 

 let into the roof and floor. The skips are collected to the 

 top of the jig by horses. On account of the height of the seam. 

 heavy draught horses can be employed. 



The winning heading to the dip is taken out in two work- 

 ings on account of the water present. First the top portion is 

 taken out as far as the position for the next bord ; then the floor 

 is lifted. The bords are made 8 yards wide, and the pillars be- 

 tween are 9 yards. 



The coal is holed by machines two Sullivan electric chain 

 machines, and one Goodman standard chain breast machine, 

 also driven by electricity. They both cut well. The Sullivan 



