May 14, 1915. THE COLLIERY GUARDIAN. 1015 UNDERGROUND TRANSPORT METHODS ON THE RAND. In the Journal of the South African Institution of Engineers (March 1915) is a paper by Mr. H. Stuart Martin, in which a description is given of the general lay-out of the Modderfontein B Gold Mine, with par- ticular reference to the methods adopted for the transport of ore underground. The paper contains some interesting particulars of the haulage equipment, which we extract. This mine is laid out on the large block system, with only one winding shaft. The pro- perty is an extensive one, measuring along the strike 12,000 ft., or 2-3 miles, and its breadth 8,600 ft., or 1-6 miles. There is only one main winding shaft, situated near the centre of the property, 1,600 ft. south of the sub-outcrop. This shaft, which intersected the reef at 578 ft., is connected up to three small prospecting shafts, Nos. 5, 6, and 7, proving the reef at a depth of about 300 ft. vertical near to the sub-outcrop, and to three winzes, Nos. 2, 3, and 4, also sunk from the surface, dipping from 25 to 27 degs., striking the reef on the incline 200 to 300 ft. from the surface, the reef dipping 15 degs. The prospecting shafts and winzes w’ere placed 1,000 ft. apart, from west to east, following the line'of sub-outcrop. During the sinking of this shaft 472 ft. were driven on one drive, one face, in a calendar month containing 27 working days, constituting a record. Two years from the date of starting active work on the property, 2,788,000 tons of payable ore were blocked out, together with 11,000 ft. of stoping faces ready for stoping. The average dip of the reef is about 15 degs. The stope faces, when sufficiently advanced, are laid with stope tracks 30 to 35 ft. apart, following the line of strike, which are kept close up to the advancing face. A permanent hauling engine is erected at the top of each stope, and a temporary one about half-way down, to expedite the clearance of rock until the central track is clear from blasting, when the permanent engine at the top of the stope is able to deal with the tonnage broken, and lower- it to the level below. Hand tram- ming is chiefly confined to the stope tracks; the distance trammed by hand is on an average about 200 ft., and does not exceed 400 ft. The centre stope track, when convenient, is cut out by a new track, and frequently stope tracks are shortened by being cut off in the stope by branch roads and dip roads, followed by the rope, half-course or diagonally across the stope. This system is similar to the longwall system of mining in collieries, the stope tracks taking the place of stall roads, and the branch tracks, rise or dip headings, cutting off the stalls. In this manner the minimum amount of rails is con- stantly employed. The back roads, as they are being cut off, are picked up and moved forward. After extensive and careful experiments it has been found most economical to place the tracks a distance not exceeding 35 ft. apart, on a dip of from 15 to 20 degs. The train of trucks hoisted and run into the stope faces varies from three to eight trucks, coupled together by strong shackles and drawbars. The empties, as a rule, are hoisted uphill, and the full trucks lowered to the level below. The ore is thus loaded into trucks at the stope face, trammed by hand to the central track or branch road, picked up by single rope haulage, and lowered to the level below, where it is hauled by ponies to the main rope (main and tail haulage), and thence to the central shaft in long trains, 60 to 100 trucks at a time. The main and tail haulage delivers its trains to an endless rope blocking haulage, which feeds the central shaft, the trucks passing through mechanically driven tipplers over the shaft bin, which is provided with coarse crushers. A detailed sketch of the shaft bottom feeding arrangement is shown in fig. 1. The rope of the endless haulage system feeding the shaft runs on the floor along a double track, the trucks being attached to the rope by Smallman clips. From the point where the trucks leave the endless rope, pass- ing through the tipplers, and back again on the empty side, the trucks run by gravity. The ore is hoisted to the surface in 6-ton skips loaded by Kimberley chutes. A low fixed truck running on 30 lb. rails, 30 in. gauge, was specially designed for the mine, and 15 in. diameter Rowbotham wheels adopted. The principal features of the truck, the construction of which is shown in fig. 2, are :—(1) A free running low truck; (2) low centre of gravity; (3) loose wheels and axles. The truck is so well balanced that it can be easily handled, and is particularly adaptable for rope haulages and running round sharp curves. The safety shackle is of special design, and is shown in fig. 3. Ore is conveyed underground by means of the follow- ing :—(1) Hand tramming; (2) horse haulage; (3) self- acting inclines; (4) stationary engines. (1) Hand tramming is all done by contract, boys working in gangs of up to five. It has been conclusively proved that the smaller the gangs of boys on contract the better the efficiency. Each truck is tallied, and each gang boy has his number and tally, which is tied on the truck and picked up at the central shaft, so that any truck not properly loaded can be traced, and -a correct record of work done by each gang or each individual is obtained. These returns are made up and reported daily. This system of hand tramming and lashing lends itself to contract work, and the boys like it. The lashing in the face, loading of trucks, and tramming to stope haulage is done by the same gang. The number of trucks thus handled per shift by gangs of boys varies up to 20 trucks per boy per shift, the average being 7-45. The price of the contract per truck (lashing, loading, and tramming)' varies from 2-J-d. to 3d. The capacity of the truck is one ton. (2) Horse Haulage. — To obtain economy in every respect in the working of horses, they should be well fed, well worked, and properly groomed and stabled; the roads should be well laid and high enough to prevent roofing, with free running and well oiled trucks. The mileage a horse will travel in a shift of eight hours t 't t w OQ £ o 8 o H CC A £ & Ph J j 3 b b b- ► *5 L 0 4 i ■ a i QQ ; < GQ 3 « o •