A HISTORY OF CUMBERLAND 



platforms are used where the different work- 

 ings connect with the inclines. 



After the level workings have reached the 

 extreme limit of the ore, either by being cut 

 off by a fault or stone trouble, or by the 

 boundary line, the work of taking out the 

 pillars is begun. When the roof is of a 

 strong character, the pillar-ore can be ob- 

 tained at considerably less cost than when 

 driving the thirls or stalls, the chief care 

 necessary being to protect the line of work- 

 ings either by pillars built of the stone that 

 may be got in working the ore, or by pillars 

 of wood or strong props. When wood is 

 employed for this purpose, old railway sleepers 

 and squared Norway timber are often used. 

 Very little ore is lost under such circum- 

 stances, probably not more than 2 per cent, 

 and where the ore is thin, the loss does not 

 reach i per cent. More care is necessary and 

 greater expense is incurred when the roof 

 consists of a softer or less sound limestone 

 or shale bed, as a much larger quantity of 

 timber is required, and in spite of all pos- 

 sible care being exercised, the superincum- 

 bent weight may cause a collapse of the 

 roof. In such cases some of the pillars may 

 have to be approached through fallen ground. 

 Then slice after slice is taken off until the 

 ore is removed. In this way the working 

 back of the pillars is carried on until that 

 supporting the main heading is reached, 

 which in the meantime is left undisturbed. 

 The heading pillars are then worked back 

 from the inside in a similar manner until the 

 deposit is exhausted. Should the ore extend 

 further to the dip, the shaft is deepened and 

 drifts or ' eyes ' are driven out at lower 

 levels. The mode of procedure in working 

 out pillar-ore is to commence at the 'rise' side 

 of the pillar, taking about 6 or 8 feet of the 

 ore as a working face and carrying it down to 

 the dip side of the pillar. When this has 

 been done, and the roof behind secured as 

 indicated, another strip of ore is in like man- 

 ner taken out. Sometimes stumps of ore are 

 left at the two corners of the pillars as a 

 means of strengthening the roof until the 

 building of the wood or stone pillars is com- 

 pleted. These stumps can then usually be 

 taken out with safety. Timber is set round 

 the pillar in some cases to keep up the roof 

 whilst the pillar is being removed. 



Where the ore-bed has been of great thick- 

 ness and two tiers of workings are rendered 

 necessary, the pillars of the top tiers may 

 sometimes have to be left as near as possible 

 over the bottom pillars, with substantial mid- 

 dlings between the workings and strong arches 

 of ore in the roof of the higher workings. 



The upper pillars are then first worked out 

 down to the sole of the top tier of workings. 

 If the roof and ore are strong and hard, the 

 working of the ore takes place from the in- 

 side outwards, but if the reverse conditions 

 are present, then the working proceeds from 

 the outside inwards, while the roof will re- 

 quire timbering. In the latter case, before 

 proceeding with the work it may be necessary 

 to support the roof of the lower workings or 

 fill them with debris (as afterwards described) 

 if this has not already been done. When the 

 top pillars have been brought back so far, as 

 much of the roof ore should be taken as can 

 be got out with safety ; round larch timber is 

 then placed across the top of the middlings 

 with the ends resting on the top of the bot- 

 tom pillars, and these are overlaid with cover- 

 wood and debris above the coverwood to a 

 depth of 3 or 4 feet. The middlings may be 

 then worked out from the bottom upwards 

 and the working of the bottom pillars after- 

 wards commenced. Should a general collapse 

 of the workings take place before all the ore 

 has been extracted, drifts are driven through 

 the fallen ground from the nearest available 

 points and the ore worked out, as has already 

 been described in speaking of robbery work- 

 ings in vein-like deposits. 



In certain conditions of the roof and ore 

 it is often considered advisable, before com- 

 mencing to remove the pillars, to pack with 

 debris the waste area round them close up to 

 the bottom of the middlings, access drifts to 

 the bottom of the pillars and 'rises' to the 

 middlings being left through the debris. In 

 this way the ore in the lower tier of workings 

 may be extracted with comparative safety, 

 even should there be a collapse of the roof 

 in the upper tier. In some mines instead of 

 taking all the debris obtained from the various 

 workings and development drifts in the mine 

 and depositing it on the spoil-bank at the 

 surface, a large portion is used for the above 

 purpose. The bed-like deposits are subject 

 to the same irregularities as those that occur 

 in the vein-like deposits, viz. nips, vertical 

 enlargements, and ' horses ' or large blocks of 

 stone intermixed with the ore. These dis- 

 turbances of course increase the cost of work- 

 ing the ore, and render the above method 

 of working liable to considerable alterations. 

 The stone blocks are left as pillars, and they 

 frequently deflect the workings from their in- 

 tended course. 



A good example of a bed-like deposit is 

 that in Postlethwaite's Fletcher pit near Moor 

 Row. The ore is of a hard nature but very 

 rich in metallic iron, and has the advantage of 

 a strong limestone roof. In consequence of 



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