DRESSING OF ORES 



105 



from constant striking, and also to reduce its weight ; tho greater the weight of head, 

 and the less in the lifter tho better. 



Arrangement is also made for giving the head a rotatory motion, so as to ensure 

 an oven wear on the face of the stamps' head." 



These stamps are driven at about 150 blows per minute, and will reduce from nine 

 to eleven tons of ore per head per day. At New Eosewarne Mine, Gwinear, 1^- ton 

 of stuff has been stamped with a consumption of 1 cwt. of coal, and from 6,000 to 

 7,000 tons of stuff with the loss of 5 tons of iron in the stamp heads. The stamps 

 are exceedingly portable, which is a great advantage, and can be taken to pieces, 

 carried to any part of the mine and erected with its portable engine in a few hours, 

 requiring but little foundation. 



A small battery may be used for prospecting purposes, and worked by horse or 

 bullock power whenever it might be desirable to do so, the machine being made 

 sufficiently portable for loading on a bullock dray. 



Jn difficult or mountainous countries, where transport is expensive and dangerous. 



