ROCKY MOUNTAIN MINE TIMBERS. 3 



The water-soaked material was placed in a small pond during the 

 summer months and the first tests were made after 60 days and the 

 last after 125 days of soaking. No means were available to give 

 complete submersion. The caps and props were tied in bundles of 

 five and the beams were rafted, iron rails being used to help submerge 

 a part of the material. At intervals of two or three days the bun- 

 dles and the individual beams were turned to make the soaking as 

 uniform as possible. 



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EMELMANU SPRUCE 



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 SHIPMENT * 



BRISTLE -CONE PINE 



"1000 2000 3000 4000 



CRUSHINS STREHQTH AT MAXIMUM LOAD - POUNDS PER SQUARE INCH 



Fig. 1.— Comparison of different species; 6-inch round mine props— air-dried and green. 

 RESULTS OF TESTS. 



Summaries of the results of the tests showing the average, maxi- 

 mum, and minimum of each group are presented in Tables 2 (props) , 

 3 (caps), and 4 (beams). Results of the individual tests on the 

 green props are recorded in Table 11, on the air-seasoned props in 

 Table 12, on the caps in Tables 13 and 14, and on the beams in 

 Tables 15 and 16. 



PROPS AND CAPS. 



The relative strength of air-seasoned and green material for each 

 species and the relative strength of the different species are shown 



