31 G W. II. WEED — TWO MONTANA COAL FIELDS. 



Sandcoulee Coal Mines. — The Sandcoulee coal mines are twelve miles 

 from Great Falls by rail and six miles east of the Missouri river. Like 

 the rest of the eon 1 Held, the country about the mines is a rolling plateau, 

 locally cut by the numerous branch coulees tributary to Sand coulee. 

 The mines are opened in the banks of one of these tributaries called 

 Straight coulee. The coal lies beneath a sandstone ledge that generally 

 outcrops upon the coulee banks, the slopes above it being generally grass- 

 covered and showing no exposures. There is a slight dip of the beds to 

 the northward, affording easy drainage and haulage. 



The property now being worked shows an excellent fuel coal that can 

 be economically mined and is near enough to the point of consumption 

 to avoid excessive freight charges. Unfortunately for the early reputa- 

 tion of the product, the working was begun in an area of "dead " coal. 

 Experience has shown that where tributary coulees have cut down the 

 overlying strata the coal has lost its virtue and is high in ash and low in 

 volatile carbon, and its physical constitution is such that it is of very 

 inferior quality. It was in such an area that the early working was done ; 

 and this, combined with the fact that in mining the entire seam, as was 

 formerly done, a large amount of slate got into the coal from the parting 

 above the lower bench (a parting that is now used as a floor in the rooms ), 

 led to unmerited prejudice against the coal from this none. 



Throughout the workings at Sandcoulee the seam shows a consider- 

 able variation in thickness, the upper benches now worked being from 

 3i feet to 7 feet thick. The quality also varies with the proximity to the 

 surface of the overlying ground in the manner already stated, and appears 

 also to depend somewhat upon the thickness of the slate roof between 

 the coal and the overlying sandrock. For the first 1,000 feet from the main 

 entry the coal is " dead,' 1 the gases having escaped through seams in the 

 sandstone roof; and the coal east of this entry is similarly affected. 



The following average section of the seam shows its character: 



Top coal 23-28 inches. 



Parting : ; " 



Coal 10 " 



Parting 1 " 



Coal 24 " 



Parting 6-8 " 



Coal 24 " 



Figure 7.— Section 



of Sandcoulee 



Coal Seam. 



