MINING 



311 



1467 



forming galleries through a mineral deposit, from its -wall or floor towards its roof, 

 and not, as usual, in the direction of its length.. This mode was contrived towards 

 the middle of the 18th century, for working the very thick veins of the Schemnitz 

 mine in Hungary ; and it is now employed with advantage in many places, particu- 

 larly at Idria in Carniola. In the two sections, Jiffs. 

 1467, 1469, as well as in the ground-plan, Jiff. 1468, the 

 wall is denoted by m m, and the roof by 1 1. A first 

 gallery of prolongation, E F, fig. 1468, being formed to 

 the wall, transverse cuts, a a, are next established at 

 right angles to this gallery, so that between every two 

 there may be room enough to place three others, b, c, b, 

 fig. 1468. From each of the cuts, a, ore is procured by 

 advancing with the help of timbering, till the roof, t, be 

 reached. When this is done, these first cuts, a, are filled 

 up with rubbish, laid upon pieces of timber with which 

 the ground is covered, so that if, eventually, it should be 



wished to mine underneath, no downfall of detritus is to be feared, These heaps of 

 rubbish rise only to within a few inches of the top of the cuts, a, in order that the 

 working of the upper story may be easier, the bed of ore being there already laid 

 open upon its lower face. 



In proportion as the cuts, a, of the first story, E r, are thus filled up, the greater 

 part of the timbering is withdrawn, and made iise of elsewhere. The intermediate 

 cuts, b, c, b, are next mined in like manner, either beginning with the cuts c, or the 

 cuts b, according to the localities. From fig. 1468 it appears that the working may 

 be so arranged that, in case of necessity, there may be always between two cuts in 



1468 



activity the distance of three cuts, either not made, or filled up with rubbish. Hence, 

 all the portion of the bed of ore may be removed which corresponds to a first story, 

 E F, fig. 1469, and this portion is replaced by rubbish. 



The exploration of the upper stories vl F', E 2 F 2 , E S F 3 , is now prepared in a similar 

 manner ; with which view shafts h h 3 , k /c 3 , are formed from below upwards in the 

 wall, m, of the deposit, and from these shafts oblong galleries proceed, established 



1469 



successively on a level with the stories thus raised over one another. See fig, 1469. 

 The following objects may be specified in the figures : 



a a, the first cuts filled up with rubbish, upon the first story E F, fig. 1468. 



b b, other cuts subsequently filled up, upon the same story. 



c, the cut actually working. 



d, the front of the cut, or place of actual excavation of the mineral deposit. 



e, masses of the barren ro;k, reserved in the cutting, for pillars of safety. 



