156 



DRESSING OF ORES 



force and action of the water. When these impediments are removed, the water is 

 repeatedly discharged from the reservoir until the waste is hushed off the ore, which 

 is found lying in holes, and around earth and fast stones, in the bed of tho rivulet. 

 A clay bottom is found to be most favourable for hushing, and tho velocity and 

 power of the stream should be proportioned to the size and density of the waste to bo 

 treated. 



FORWARDING AND LIFTING APPARATUS. 



Besides the machinery required for the enrichment of ores, it is a matter of great 

 importance to introduce such auxiliary arrangements as shall not only facilitate actual 

 dressing, but also be in themselves somewhat inexpensive. In this division, as in 

 every other, the means should be strictly adapted to the end, and ought not to bear 

 a cost disproportionate either to tho circumstances or prospective advantages of an 

 undertaking. 



The shovel, fig. 761, usually employed in British mines is of triangular shape, and 

 made of good hammered iron pointed with steel. Tho dimensions vary, but one of 

 an average size is about 11 inches wide at the top, and 13 inches from the point to 

 the shank, weight 4 pounds, and costs one shilling ; to which must be added, five 

 pence for tho hilt, or handle. The hilt should be of ash, free from knots and slightly 

 curved, 



761 762 



Picking Boxes, Jig. 762, are employed for the purpose of collecting tho prill and 

 dradge ore from the stuff with which it may be mechanically intermixed. These boxes 

 or trays are handled by children. They are made of deal, 1 inch thick, of tho fol- 

 lowing dimensions : Length, 16 inches ; depth, 7 inches; width at bottom, 7 inches; 

 width at top, 10 inches ; and cost about Is. Sd. each. A ledge of wood to serve as a 

 handle is sometimes nailed to the ends of the box. 



Wheel-barrow. The sides, ends, and bottom, are composed of deal l inch thick. 

 The ends are mortised to the sides, whilst the bottom is generally fastened by means 

 of nails, and bound with slips of hoop iron at tho angles. Hoop iron is also employed 

 to protect the upper edges of the barrow. The wheel is often made of wrought iron, 

 ($ round) and 14 inches diameter. Its axes rotate in wrought-iron ears. Tho extreme 

 length of the sides of a well-proportioned barrow is 60 inches, depth at centre 9 

 inches ; the ends are inclined as shown in the fig. 763. Tho cost of a barrow with 

 wrought-iron wheel complete, will vary from 6s. 6d. to 7s. 



764 



765 



Hand Barrow. When large quantities of stuff have to bo removed from place to 

 place on the surface, and where it would be inconvenient to use tho wheel-barrow, a 



barrow having handles at both ends is employed 

 (Jig. 764). It is made of deal plank \\ inch tliii-k ; 

 tho length of tho sides is 5 feet 6 inches; depth in 

 centre, 9 inches; width, 18 inches at top and 10 

 inches at bottom; length, 24 inches at top and 18 

 inches at bottom ; cost complete about 4s. Gd. 



Railroads. The gauge of surface roads varies from 

 15 inches to 2 feet 6 inches within tho rails. In- 

 stead of manufactured rails, common flat wrought 

 iron, 2 inches wide and inch thick, is oftentimes 

 employed. An extremely servicoablo r;iil is formed 

 of a strip of timber 2 inches square, upon which is 

 laid wrought-iron, l\ inch wide and inch thick, 

 fastened by means of nails or screws. 



Tram Waggon and Turn-table. A tram wag- 

 gon and tiirn-tablo is shown fig. 765. Tho waggon 

 built of wrought iron, with cast-iron wheels. Tho latter are usually 12 inches diameter, 



