A Treatise on Mine-surveying |
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Page 10
... equal to two right angles , and that the sides of the triangle are proportional to the sines of the opposite angles . right - angled triangles the most useful formulę are— For b = a sin B c = a cos B = C = b tan C b c tan B b = c cotan ...
... equal to two right angles , and that the sides of the triangle are proportional to the sines of the opposite angles . right - angled triangles the most useful formulę are— For b = a sin B c = a cos B = C = b tan C b c tan B b = c cotan ...
Page 11
... equal to 1 mile . This length was chosen by the inventor , Edmund Gunter , in 1620 , with the object of facilitating the computation of areas ; 10 square chains being equal to 1 acre . The chain is composed of 100 links of iron or steel ...
... equal to 1 mile . This length was chosen by the inventor , Edmund Gunter , in 1620 , with the object of facilitating the computation of areas ; 10 square chains being equal to 1 acre . The chain is composed of 100 links of iron or steel ...
Page 15
... equal to the required correction . The preceding table gives the correction for each chain measured on the slope . In order to save calculation , many mining dials and theodolites have the correction for declivity marked on the ...
... equal to the required correction . The preceding table gives the correction for each chain measured on the slope . In order to save calculation , many mining dials and theodolites have the correction for declivity marked on the ...
Page 16
... equal to each other , and the distance BC is measured . B B D Fig . 2 . Fig . 3 . Fig . 4 . This measured distance will then be equal to the required dis- tance , A D. In order to erect a perpendicular to a line at a given point ...
... equal to each other , and the distance BC is measured . B B D Fig . 2 . Fig . 3 . Fig . 4 . This measured distance will then be equal to the required dis- tance , A D. In order to erect a perpendicular to a line at a given point ...
Page 17
... equal to BC · AB When the obstacle can be chained round , but not chained across nor seen over , the inaccessible distance may be determined by means of parallel lines . Thus in Fig . 5 , from A and B two points in the station - line on ...
... equal to BC · AB When the obstacle can be chained round , but not chained across nor seen over , the inaccessible distance may be determined by means of parallel lines . Thus in Fig . 5 , from A and B two points in the station - line on ...
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Common terms and phrases
accuracy accurate adjusted back-sight base-line bearing bore-hole brass calculated centre chain City Guilds clamped clinometer coal colliery collimation colour compass compass-box contour lines cord corner cosec cotan cross-wires curve determined direction distance employed equal error fathoms feet fixed fore-sight glass graduated ground height hole horizontal circle inches inches in diameter inclination instrument intersection latitude length lode magnetic bearing magnetic meridian magnetic-needle marked means measured method metres mine-surveying miner's dial mines needle observations obtained offsets Ordnance Survey parallel parallel ruler perpendicular placed plane plate plotting plumb-bob plumb-line plummet position protractor represented right angles safety-lamp scale seam shaft side Silver King spirit-level square staff station station-line strike and dip surface surface-surveys survey tacheometer tacheometry taken tangent screw telescope theodolite transit-theodolite traverse triangle tripod tube underground vernier vernier-plate vertical angles wire yards zero