A Treatise on Mine-surveying |
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Page 7
... inches , whilst at New York it is 39-1017 inches . The second plan was therefore adopted - that is , a fraction of the earth's meridian was taken as the standard . For this pur- pose , at the time of the French Revolution , the distance ...
... inches , whilst at New York it is 39-1017 inches . The second plan was therefore adopted - that is , a fraction of the earth's meridian was taken as the standard . For this pur- pose , at the time of the French Revolution , the distance ...
Page 8
... inches . For mine - surveys the metre is the unit now almost exclusively used in continental European countries . It is also employed on Government surveys in the United States . Special units of length used for mining purposes in ...
... inches . For mine - surveys the metre is the unit now almost exclusively used in continental European countries . It is also employed on Government surveys in the United States . Special units of length used for mining purposes in ...
Page 11
... inches . All calculations with chains and links can thus be easily performed by means of decimals . The following table will be found useful for converting chains into feet and feet into links : - CHAINS INTO FEET . FEET INTO LINKS ...
... inches . All calculations with chains and links can thus be easily performed by means of decimals . The following table will be found useful for converting chains into feet and feet into links : - CHAINS INTO FEET . FEET INTO LINKS ...
Page 13
... inches in length . The chain is some- times made entirely of brass . No advantage is gained by using Gunter's chain ... inch is to be preferred to the link as a unit . Chaining on Slopes . - In chaining up or down a slope , the distance ...
... inches in length . The chain is some- times made entirely of brass . No advantage is gained by using Gunter's chain ... inch is to be preferred to the link as a unit . Chaining on Slopes . - In chaining up or down a slope , the distance ...
Page 15
... inches . It should be tested frequently , particularly after use in a wet mine . It is not advisable to use offsets more than a chain in length . When the offset does not exceed this length , with practice the eye may be relied upon to ...
... inches . It should be tested frequently , particularly after use in a wet mine . It is not advisable to use offsets more than a chain in length . When the offset does not exceed this length , with practice the eye may be relied upon to ...
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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