290 NEW YORK STATE MUSEUM 



account of the incidental wear and damage in the rapid operations 

 of paper manufacture as carried on in most mills. 



Many of the mines are owned independently of the operative 

 companies, to whom they are leased on a royalty based on a 

 specified amount per ton and requiring the extraction of a certain 

 minimimi tonnage each year. The royalties vary rather widely, 

 but in every case are rather high for a low-priced product Uke talc, 

 of which the cost of preparation is proportionately high. The royal- 

 ties on some properties run as high as 75 cents a ton; and the lowest 

 reported are around 25 cents a ton. 



Milling. The reduction of talc to the degree of fineness ordi- 

 narily required of the product is a simple but not inexpensive process, 

 which requires an extensive equipment of crushing and grinding 

 machinery. Talc is one of the softest minerals known, yet in the 

 natural state possesses a degree of cohesion and toughness which 

 renders its comminution no easy matter. This is true in regard to 

 both the felted fibrous variety and the foliated talc; massive talc 

 may be more easily pulverized. 



In St Lawrence county processes now employed have been gradu- 

 ally evolved from experimentation extending over a long period of 

 years. The first output was ground in buhrstones, like those 

 employed in grain mills. The demands of constraiers have necessi- 

 tated the adoption of more elaborate methods that can be depended 

 on to yield the desired quality and uniformity of grade. 



Practically all the output is ground in the district by milling 

 plants situated along the Oswegatchie river, which supplies most 

 of the power thus used. They are distributed along the river from 

 Talcville, 2 miles below Edwards, to Hailsboro, 3 miles above Gouv- 

 erneur. Altogether the mills have a combined capacity of nearly 

 100,000 tons of prepared talc a year; but the full capacit^T- has never 

 been continuously employed. 



The grinding of the talc is accomplished in several stages. The 

 process varies with each mill, as there is no standard practice further 

 than that the final stage is always carried out in revolving cylinders 

 loaded with pebbles. The first step is to break the lump talc in a 

 crusher to about i^ inch size; for this a jaw crusher may be employed. 

 The product then is reduced to one-half of an inch or less in size 

 by rolls, after which it is ready for grinding, which is performed by 

 two stages. In the first a wide choice of apparatus is exemplified 

 by the different plants — the equipment including buhrstones, 

 centrifugal grinders like the Griffen mill and conical pebble mills. 

 The talc is then passed through a bolt of about 60-mesh and is ready 



