STANFORD MERTHYR COLLIERY. 343 



in. At first the chock was used singly, but it was found to 

 slew the skips oft' the track, so now^a pair are used together. 

 Ordinary chocks are placed on the incline in case a horn of 

 the creeper chain should break, and set the skips free. The 

 creeper chain is tightened by screwing up a sliding pulley ; if 

 the chain stretches too much, a link is taken out. 



The loaded skips are run into balanced side tipplers , where 

 they are held in place by angle iron fixed just above their 

 wheels. The empty skip is pushed oft' by the On-coming full skip, 

 and runs down an incline towards the mouth of the tunnel. 

 Two or three check brakes are placed along the line, so as to 

 control the speed of the skips. This brake is the invention of 

 Edward Davies, the company's engineer. It consists of a bar 

 of angle iron arranged over each rail, so that it can come in 

 contact with the tread of the wheel. That end of the angle- 

 iron on the up side swings on a bolt, and is raised a little 

 higher oft the ground than the top of the wheels, so that the 

 latter can pass under it easily, but the exit end is free and 

 weighted, so that it presses on the tread of the wheels that 

 pass underneath it. Such brakes may be made so that they 

 can be raised by hand (Fig. 213), and release the skip should 

 it be held fast. 



From the tippler the coal falls on to a screen. A double 

 gate is arranged part of the way down each screen. It is kept 

 in place by weights, and can be opened by pulling a rod. The 

 round coal is allowed to fall into a counterbalanced shoot. 

 When lowered, the shoot drops the coal into waggons, thus 

 saving shovelling. The slack falls through the screens into 

 slack boxes, from which it can be loaded into waggons, but if 

 there are no orders to be carried out, the slack is taken by 

 scraper conveyors up to storage slack boxes capable of holding 

 a little over 2000 tons. (Fig. 214.) The scraper conveyor is 

 kept down at the hollow by sprocket holding-down pulleys. The 

 creeper chain and scraper conveyor are worked by an old jig 

 rope, the different sections being thrown in and put of gear 

 by friction clutches. The tightening pulley and weight for the 

 rope is shown in Fig. 215. There are several horizontal slid- 

 ing gates in the "bottom of the storage slack boxes, so that if 

 required a train of 40 waggons can be quickly loaded by pass- 

 ing underneath, men on platforms opening the gates with 

 lever handles. A scraper conveyor also takes coal to the Lan- 

 cashire boilers. The boilers have a bar in front of the fire- 

 box for tools to rest 011 when cleaning them out. There is a 

 special door at the back of the screen-box, through which the 

 miners obtain the supply of coal allowed them for domestic- 

 purposes. 



