NEWCASTLE A. AND B. PITS. 287 



{Fig. 1ST) has a sliding bottom, with a hooked bar attached 

 io it, that strikes an iron finger, which can be fixed to sleepers 

 over any part of the box required. The automatic device 

 consists of a piece of iron, bevelled on the up hill side, and 

 straight on the lower; this gradually pushes the door open, 

 and finally passes under it, as the door is not parallel with the 

 rails. On returning, the door passes over the projection 

 without touching it, and a boy pushes the door back before 

 filling the hopper skip again. The hopper skip is drawn up 

 an incline, over the coal boxes, by means of a rope wound up 

 by a special engine. As the lower portion of the incline 

 would be in the way of the waggons going under the screens 

 if it was left permanently down, it is made to draw up on a 

 hinge when not in use. 



1ST. --Hopper Skip. 



The air current is induced by a Waddle fan 21ft. in dia- 

 meter, which makes 80 revolutions per minute, when the mine 

 is working, but the speed of the fan is reduced to 60 revolu- 

 tions per minute otherwise. Though comparatively small, 

 this fan has a greater capacity than a larger one of the older 

 type, for it is fitted with a trumpet-shaped rim, and the blades 

 are bent back so as to throw out the air, instead of being 

 turned the other way, which scooped some of the air back 

 again. 



The colliery is unwatered by means of two electrically- 

 driven pumps and two steam pumps. 



The generator was provided by the General Electric Co., 

 and is built for 90 amp. and 560 volts. It is driven by an 

 Ames Iron Works engine. The cables underground are tied 

 to bobbin insulators, with niarlin. In case of a fall of roof, 

 Hie niarlin will give way first, and may thus save the cable. 

 At the entrance to a gateway the cable is bared, so that the 

 trailing cable can be clipped on. When not in use, the b'ared 

 portion is protected by a wooden block clamped over it. 



The steam plant consists of a Babcock and WTlcox boiler, 

 which generates high pressure steam (1201b.) for the electric 

 plant; there are also two Lancashire boilers and a nest of 



