E/MJ : engineering and mining journal . erally in use) from the stopeplan to the horizontal plan. The secondary pantograph isso arranged that the arms can be set to allow for expansionor contraction of the two plans. Among several other schemes of reduction, one thatmerits attention ami that may be converted mechanicallyis that represented by Fig. 9. This apparatus effects thecombination of the component of motion of the tracingpoint of the pantograph parallel to the line of strikereduced in the ratio of the stope plan to the horizontal plan, with the component parallel with the dip line re-du
E/MJ : engineering and mining journal . erally in use) from the stopeplan to the horizontal plan. The secondary pantograph isso arranged that the arms can be set to allow for expansionor contraction of the two plans. Among several other schemes of reduction, one thatmerits attention ami that may be converted mechanicallyis that represented by Fig. 9. This apparatus effects thecombination of the component of motion of the tracingpoint of the pantograph parallel to the line of strikereduced in the ratio of the stope plan to the horizontal plan, with the component parallel with the dip line re-duced to the combined ratio of the proportions of thestope plan to the horizontal plan, with the ratio of thecosine of the angle of dip to 1, the locus of intersectionsof the components being the required reduced to the diagram, if the tracing point T of a pan-tograph FDRT is guided over the line TL, representinga single bench of a stope-face contour, then the reducingpoint I! will trace out RU, TL being reduced propor-. FIG. 9. COMBINATION COSINE AND SCALE PANTOGRAPH OPERATION TO GET HORIZONTAL VALUES OF ANY REQUIRED REDUCTION tionally in the ratio of the stope plan to the horizontalplan to RU, provided the arms RN, RB, DT and DFare set to the same ratio; the component TH parallel tothe dip line OY being reduced to RH and the componentHL, parallel to the line of strike OX reduced to HLin the same ratio as TL. Now if two auxiliary arms YEand VA are attached to TD and DF respectively andset to the ratio of the cosine of the angle of dip 1 multi-plied by the ratio of the stope plan to the horizontal plan,then as the tracing point T is moved from T to L, Vmoves to T7; TL, TH, HL are reduced to W, VK,KY in this combined ratio. If. at the beginning of movement of T, a square CGU isplaced with edge GC in contact with Y, contact beingmaintained throughout movement of T, with GC parallelto OY and hence OV parallel with OX, then as T is movedto L, C moves to C ; CK-YK is
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Keywords: ., bo, bookcentury1900, bookdecade1910, booksubjectmineralindustries
