300 MINING 



in a line which approaches either towards its inclination or its direction. The Cornish 

 miners use two different terms to denote these two modes of rejection ; for the first 

 case they say the vein is heaved, for the second it is started. 



The great copper lode of Carharack (d, fig. 1447), in the parish of Gwennap, is an 

 instructive example of intersection. The thickness 

 1447 f of this vein is 8 feet; its direction is nearly east 



and west, and it dips towards the north at an in- 

 clination of 2 feet per fathom ; its upper part being 

 in the kttlas (a greenish clay-slate), its lower part 

 in the granite. The lode has suffered two inter- 

 sections : the first produced by meeting the vein h, 

 called Stevens 's fluckan, which runs from north-west 

 to south-east, and which throws the lode several 

 fathoms out ; the second vein is produced by another 



vein, i, almost at right angles with the first, and which occasions another out-throw 

 of 20 fathoms to the right side. The fall of the vein occurs therefore in the one 

 case to the right, and in the other to the left ; biit in both it is towards the side of 

 the obtuse angle. This distribution is very singular, for one part of the vein appears 

 to have mounted while the other has descended. N, s, denotes north and south, d is 

 the copper lode running east and west ; h, i, are systems of clay-slate veins called 

 flwkans ; the line over s represents the downthrow, and d' the up-throw. 



There is a great want of exactness of expression in the terms used to describe the 

 phenomena of dislocations. The foregoing paragraphs are strictly according to the 

 technical language of the miner, who usually regards the cross-courses, here called 

 fluckans, as being the cause of the alteration in the mineral veins, whereas they are 

 themselves merely the effect of the general movement of the rock masses. The sin- 

 gularity alluded to disappears if the woodcut be regarded as a cross-section repre- 

 senting the result of two distinct movements in a direction from the observer. See 

 FAULTS. 



In different districts in this country the terms used to distinguish mineral veins 

 vary considerably. The following terms prevail in Derbyshire and the north of 

 England. 



Lodes or mineral veins are usually distinguished by the miners of these districts 

 into at least four species : 1. The rake vein ; 2. The pipe vein ; 3. The flat or 

 dilated vein ; and 4. The interlaced mass (Stock-werke), indicating the union of a 

 multitude of small veins mixed in every possible direction with each other, and with 

 the rock. 



1. The rake vein is a mineral fissure; and is the form best known among prac- 

 tical miners. It commonly runs in a straight line, beginning at the superfices of the 

 strata, and cutting them downwards, generally further than can be reached. This 

 vein sometimes stands quite perpendicular ; but it more usually inclines or hangs 

 over at a greater or smaller angle, or slope, which is called by the miners the hade or 

 hading of the vein. The line of direction in which the fissure runs, is called the 

 bearing of the vein. 



2. The pipe vein resembles in many respects a huge irregular cavern, pushing 

 forward into the body of the earth in a sloping direction, under various inclinations, 

 from an angle of a few degrees to the horizon, to a dip of 45, or more. The pipe 

 does not in general cut the strata across like the rake vein, but insinuates itself be- 

 tween them ; so that if the plane of the strata be nearly horizontal, the bearing of the 

 pipe vein will be conformable ; but if the strata stand lip at a high angle, the pipe 

 shoots down nearly headlong like a shaft. Some pipes are very wide and high, 

 others are very low and narrow, sometimes not larger than a common mine or drift. 



3. The flat or dilated vein, is a space or opening between two strata or beds of 

 stone, the one of which lies above, and the other below this vein, like a stratum of coal 

 between its roof and pavement: so that the vein and the strata are placed in the same 

 plane of inclination. These veins are subject, like coal, to be interrupted, broken, and 

 thrown up or down by slips, dykes, or other interruptions of the regular strata. 

 In the case of a metallic vein, a slip often increases the chance of finding more 

 treasure. Such veins do not preserve the parallelism of their beds, characteristic 

 of coal seams ; but vary excessively in thickness within a moderate space. Flat veins 

 occur frequently in limestone, either in a horizontal or declining direction. The flat 

 or strata-veins open and close, as the rake veins also do. 



4. The interlaced mass has been already defined. The interlaced strings are more 

 frequent in primitive formations, than in the other's. 



To these may be added the accumulated vein, or irregular mass (Entzenu'crke), a 

 grave deposit placed without any order in the bosom of the rocks, apparently filling 

 up cavernous spaces. 



