X, A, 4 



Pratt: Petroleum and Residual Bitumens 



271 



If petroleum were available in quantity at a cost which would 

 make it a competitor with imported coal as fuel, the present 

 Philippine petroleum consumption would be multiplied. Inter- 

 island steamships and the railroads would undoubtedly adopt oil 

 fuel, and these factors alone would greatly increase the market 

 for petroleum. 



With the residual bitumens, however, the case is different. 

 The rock asphalt from the deposit at N may prove valuable as a 

 paving material. Two representative samples of the rock as- 

 phalt yielded 6.30 and 8.84 per cent of bitumen, respectively. A 

 sample from the rich lower portion of the deposit contained 61.85 

 per cent of bitumen. Probably the average grade of material 

 carries from 6 to 10 per cent of bitumen. The rock asphalt 

 most widely used in Europe carries from 6 to 8 per cent of 

 bitumen. Other rock asphalts carry from 10 to 12 per cent 

 of bitumen, but are mixed with poorer materials for use. It 

 is stated that a rock-asphalt pavement should contain from 7 

 to 10 per cent of bitumen. 



One of the principal objections to rock asphalts has been 

 the contention that the bitumen is usually insufficiently asphaltic 

 in character to make a good binder in pavements. In the follow- 

 ing table are analyses of the rock asphalt from the outcrop 

 at N compared with analyses of sheet-asphalt pavement and 

 with analyses of rock asphalts from Oklahoma, which have 

 been proved to be of superior quality for paving : 



Table X. — Analyses of rock asphalts and sheet asphalts." 



Source. 



Total bi- 

 tumen. 



Petro- 

 leum. 



Asphal- 

 tene. 



Outcrop N, Villaba, Leyte 



Sheet-asphalt pavement: 



Muskogee 



Oklahoma 



Rock-asphalt pavements in Oklahoma 



Per cent. 

 [ 8.84 

 I 6.30 

 13.5 

 9.1 

 11.0 

 7.85 

 10.10 

 9.80 



Per cent. 

 56.0 

 58.0 

 90.1 

 67.1 

 78.1 

 78.81 

 72.65 

 70.61 



Per cent. 

 44.0 

 42.0 

 9.9 

 32.9 

 21.9 

 21.19 

 27.35 

 29.39 



" First analyses by A. H. Wells, chemist, Bureau of Science. Other analyses are from 

 Oklahoma Geological Survey Circular 5 (1913), 18. 



The Leyte rock asphalt has more asphaltic constituents than 

 the rock asphalt from Oklahoma, which is a superior paving 

 material. Consequently no insufficiency of asphaltic compounds 

 can be charged against the Leyte rock asphalt. It is even 

 possible that it is too high in asphaltic constituents and will de- 



