356 University Geological Survey of Kansas. 
Summary. 
To the maintenance cost, $33.40, add the cost of deprecia- 
tion, $16.03, and we get $49.43 for the cost of maintaining 
a plant per day. If the mill is a 100-ton capacity mill, which 
is seldom or never attained, the cost for treating one ton of 
ore would be about 50 cents. Reckoning that only 75 tons 
are treated, which is a fair average capacity for the mills in 
this district, the cost per ton would be 66 cents. If 60 tons 
are treated, which is not uncommon, the cost per ton would 
be 83 cents, etc. 
Comparing these figures with those obtained from custom 
mills in the district, we see that the price charged by the 
mills is $1.25 for rough and $1 per ton for hand jig dirt. 
This includes the cost of hauling the material to the mill, 
which varies from 18 to 25 cents, depending on the accessi- 
bility and character of the material. If 20 cents per ton be 
taken as an average price for hauling, and to this add the cost 
per ton for a mill of a capacity of-60 tons per day, the cost 
of treating per ton would be $1.03. If, however, the mill is 
run on its own dirt, the cost per day will be that given 
above, 83 cents, plus the wages of the trammer, which is 
$1.75 per day, or 3 cents per ton (60-ton mill), which gives 
86 cents per ton. Naturally the cost of hoisting would figure 
into the cost of bringing the dirt to the mill; but as this has 
been taken up under another head, we omit introducing it at 
this point, especially as we are comparing with the actual 
price charged for concentrating in a custom mill, in which 
case the cost of hoisting is not figured. ‘The prices for treat- 
ing ore vary from 90 cents to $1.25 per ton, giving a saving 
of 4 cents in the first case, and 39 cents in the latter case 
over what would have to be paid out for treatment. 
The character of the material associated with the ore has 
much to do with the ease and rate of its concentration. Oc- 
casionally shale (commonly called slate) occurs in connec- 
tion with the ore bodies; clay is also of common occurrence. 
Both of the above-named materials affect the treatment to a 
marked degree, even reducing the capacity of the mill from 
60 to 45 tons. An extra large amount of water must be used 
