576 
MANGANESE DEPOSITS OF INDIA : MINING. [PaET III : 
the surface, i In^^the neighbouring mountains, an extensive system of reservoirs 
and flumes was then constructed, ending in a small masonry tank above the mine, 
from which a steel pipe, crossing on a trestle the deep gulch above referred to, 
jeads the water to a nozzle in the working place. The tank is now 224 ft. higher 
than the nozzle, and the discharge is 640 gal. per minute. 
' The wash from the clay banks thus attacked is allowed to settle in the bed 
of the working place, so that only the clay is carried off in the overflow down the 
drainage shaft. The sand and gravel, together with the big fragments of ore, 
are then collected in cars travelling on movable tracks, and carried to the washing 
plant, close to the edge of the pit. The area now under work covers 5J acres, and 
a depth of 56 feet below its present level will have to be gained before the untouched 
ore will become available. The entire output now comes from ground that was 
overlooked by the earlier workers. An ordinary section of clay bank, in which 
no especially hea^'y lumps are encountered, will carry around 10 per cent., by weight, 
of. manganese oxides. Wad, which is rather abundant in some spots, can not be 
saved in this way, and is lost. In any case it would require calcining to bring it 
up to shijjping grade. 
' A steam shovel is used for removing the gravel overburden. Trains of dumping 
cavi are brought around to it, on track laid clos^ to the edge of th? pit, loaded, 
and drawn off to a wast? dump at some distance from the mine, at a total ccst of 
about 6(?. per cu. yd. Waste from the washery is disposed of in the same way . 
Washery Operations. 
' Th3 washery has a double-tracked incline extending from its top floor to the 
bottom of the pit, and carrying a pair of self-dumping skips. The loaded cars 
from the pit, whose contents still retain a lot of adherent clay, dmnp into a sump 
which is kept half full of water, so as to cause the material to flow easily. The 
mixture is then drawn off through gates into the skips and hoisted to the top of 
the washery. Here it passes into an inclined double logwasher fed abundantly with 
water, where most of the clay is washed oft" and discharged. The lumps then go 
through a crusher and into another, but horizontal log^\asher, where the last clay 
is removed. 
' The discharge from this washer goes into a trommel with |-inch holes ; the 
oversize passes to picking belts where waste is discarded and the ore becomes 
ready for market. The undersize goes to another trommel, which makes four 
sizes, and each size falls into a separate jig. The JlcClannahan jig has proved 
admirably suited for this work and makes a clean separation into heads and tails, 
■with no middling product. The tails, carrymg 3 or 4 per cent, of manganese, are 
sold to foundries and basic steel makers. The waste from the picking belt some- 
times carries as much as 20 per cent, manganese. A great deal of this waste is 
in the form of quartzite conglomerate, manganese oxide being the cementing agent, 
and, if crushed again, might yield some good ore ; the management, however, is 
s toring this material until it can find a market, it being worth more than jig taiUngs. 
' No attempt is made to reduce the size of the ore, the management preferring 
to sell its product in lump form to the steel industry It is probable that the small 
additional outlay for grinding equipment would prove a good investment, smce the 
other consuming industries, the glass, the paint, and the storage battery manu- 
factvuers, are accustomed to pay about-double the price allowed by the steel 
makers. 
' The lump ore shipped from the mine averages around 48 per cent, metallic 
manganese, and occasional lumps reach nearly to 60 per cent. Phosphorus rarely 
