March 



1914. 



THE INDIA RUBBER WORLD 



287 



gutta-percha lor use in power and lighting cables in and 

 near mines. Many domestic and South American mines that 

 are 10.000 to 12,000 feet above sea level, and that are 

 hundreds of miles from woodlands and coal mines could not 

 be worked at a profit with steam power, hut are paying well 

 under electric power. There are none but electric mine 

 hoists in thousands of dividend-paying mines opened within 

 a decade, and all modernly equipped mine.* are using electric 

 lights ; so that this means a continuously enlarging market 



Gold Dredge .\t Fe.\tiier River, C.\liforxia. 



in tlie mining industry for insulated cables and wire. The 

 power and ligiiting capacity of all the mining plants in the 

 Three Americas being accurately known by engineering 

 societies, it is demonstrable that the insulated wire in use is 

 not less that the equi\alent of eighteen girdles of wire 

 around the equator. 



.All makers of pneumatic tools relate that the mineral 

 industry is daily increasing purchases in this field. The 

 greater mines, as the Anaconda, and Calumet & Hecla, make 

 a great deal of the compressed air machinerj' and tools 

 wliich they use, and their machinery shops carry large 

 stocks of hose and packing of special kinds made for steam, 

 hydraulic, compressed air and pneumatic machinery. A big 

 gold dredging plant in Montana that was designed and set 

 up by the late Prof. N. S. Shalcr, of Harvard University, is 

 an interesting example of the uses of the best kinds of rubber 

 hose, packing, special patterns of molded rubber goods and 

 of gutta-percha-covered power cables and good insulated 

 wires for the lighting plant. The plant is run with three 

 eight-hour shifts of crews, and is highly profitable. Only 

 the very best of rubber products is bought. Wherever 

 enough water can be had to float a gold dredge, they are 

 at work, and the industry is extending, as also is gold dredg- 

 ing by hydraulic methods. In both departments the con- 

 sumption of suction and other kinds of hose is large. 



In Alaska alluvial gold deposits are being worked where 

 the ground is frozen fifty to sixty feet below the surface. 

 Low cost petroleum from California has enabled miners 

 to thaw the tundra to the depths where gold is found. 

 Another important factor in this arctic-like winter industry 

 is the high working properties of rubber hose and packing 

 made with special reference to these uses. Good grade 

 rubber hose is a prime factor in the economical working of 

 alluvial gold mines in areas of our country that for a single 

 year will show a yield of refined gold worth over $10,000,000 

 at the United States Assay Office. 



The accompanying illustrations of gold dredges, known in 

 the mining industry as "gold ships," show types that are made 



near the workings. These dredges cost from $25,000 to $75,- 

 000 each, and are employed wherever there is water enough 

 to float them. In many instances the dredge digs the pound 

 in which it is worked. The foreground, showing the hills 

 (see illustration \o. 6), is worked for gold by means of long 

 lines of hose attached to powerful pumps. The streams from 

 the hose wash out considerable alluvial gold, including good 

 sized nuggets. There are 2,387 gold dredges of the latest 

 patterns at work in North, Central and South America, and 

 almost 1,500 in Asia, Australia and New Zealand. A recent 

 report of a gold dredge worked in California is as follows: 

 Cost of the dredge, $50,000; worked 500,000 yards that yielded 

 20 cents worth of gold per yard ; net profit $83,000 — being 

 128 per cent, per annum on investment. A miner panning 

 alluvial gold cannot work more than one cubic yard a day, 

 and the value of the gold therein must be at least $3 to $4 

 to pay him fair returns, whereas a dredge can make money 

 by working over old placers given up by Chinamen content 

 to make a dollar a day. The dredge business is in its infancy. 

 A very small percentage of the known alluvial gold deposits 

 has been worked by these machines in North America. This 

 branch of mining buys india rubber goods in hose, packing. 

 Inciting, boots, jackets and hats estimated, at retail prices, as 

 amounting to $1,875,000 a year, for all countries. Because 

 most of the dredges and hydraulic gold mining plants are 

 remote from sources of supplies, none but the very best 

 grades of rubber hose, packing, belting, boots and clothing 

 are bought. 



India rubber boots, jackets, coats and hats are worn by 

 850,000 miners in North .'\merica in what is denominated "wet 

 mines" — that is, mines in which, but for the pumping plants 

 kept going all the time, the work could not be carried on. In 

 this country's wet mines 150,000,000 tons of water are pumped 

 every year. Estimating the annual purchases of india rubber 

 clothing and boots and hats for the mining interest of North 

 .\nierica, and upon the basis of known sales made by the 

 stores maintained by a score of mining corporations whose 

 main purchasing offices are in New York, the total sum is 



Gold Dredging in Mont.an.a. 



$18,350,000, at retail prices. For mining engineers and man- 

 agers of mines, special designs in boots and jackets and caps 

 and hats of india rubber are made of the very best materials. 

 The most popular patterns of india rubber garments worn 

 by miners are almost the same in design as those made for 

 President Andrew Jackson by the Roxbury India Rubber Co., 

 when he visited Boston in 1834 



Among the Mexican native miners there is a good demand 

 for the old style india rubber poncho, which is a blanket 



