REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1902 rlOl 



material is conveyed from the mine to the mill in cars drawn 

 by mules. This company at the present lime owns and has 

 under lease 100 acres of land underlain by plaster rock. The 

 company has just opened a new shaft at this level, a few hun- 

 dred yards south and west of the old opening, which, they expect, 

 will increase their output. A vertical shaft in the mine pene- 

 trates at the depth of 7 feet, another bed of plaster 5 feet in 

 thickness. It is planned to work this, and a horizontal shaft 

 has been begun at the creek side. A third and still lower level 

 for gypsum is reported as existing. 



The gypsum is used here in the manufacture of the three sub- 

 stances, land plaster, stucco or plaster of paris (the name given 

 to the product when calcined), and wall plaster. Steam power 

 is used in the mill. 



The land plaster is made by running the raw plaster rock 

 first through a nipper, then a cracker of coffee mill type and 

 then grinding it between burstones. 



For stucco, the material is subjected to the first two stages 

 of the above process, by which it is broken into fragments about 

 the size of a pea, when it is taken to the calciner. The process of 

 calcining is what is known as the Cummer process. The material 

 is conveyed by a bucket elevator to a rotary kiln or drum, a 

 cylinder inclined a few degrees from the horizontal, over a fire, 

 fueled with soft coal from an automatic American stoker, the 

 material being kept constantly mixed by being carried up to 

 a certain point by shelves lining the interior, when it falls down 

 again. From here the material is conveyed into brick cooling 

 bins. When cooled, it is ground with emery stones and comes 

 out stucco, ready to be put up for shipping. This material is 

 shipped in bulk, also in jute bags. 



The dry mortar wall plaster is made by the Diamond Wall 

 Cement Co., who occupy the west end of the building. The mix- 

 ture is two parts sand and one of stucco, with a small proportion 

 of hair and retarder. 



The sand is obtained at Wheatland Center, 2 miles west, on 

 the line between the farms of Frank Kingsbury (Wheatland 

 Center) and Albert Mudge (Rochester). During the last year, 



