bituminous sand can be seriously considered as a paving material

94

In conclusion Ells says:

“Tt is thus safe to say that, even apart from the actual merits of any of the processes that have been used, the extraction of bitumen from bituminous sand-rock has not met with commercial success. Nevertheless, in view of the various factors that must be taken into account in considering past attempts, it is difficult to say whether, under the most favourable conditions, commercial extraction may or may not be feasible. Meanwhile, those who may care to attempt extraction on a commercial scale and under conditions prevailing in northern Alberta, will have available the results of many years’ elaborate and often costly experimentation, on which to base their efforts. Further, it should be remembered that, owing to freight and other charges on imported asphalits, extraction in Alberta would be on a more favourable basis than has, for example, been the case in California, where competing residuum can be sold at a very low figure.”

Material for Road Construction. The applicability of bituminous sands to road construction is dependent on the character of the mineral aggregate, and the proportion and character of the contained bitumen.

Examinations have been made of the grading of the sand in a number of samples and it has been found that in this respect much of the Alberta material is unsatisfactory. “It is, however, possible that a further and more detailed investigation of individual deposits will show that a combination of material from two or more localities will result in a satisfactory grading of the aggregate.”

“In general, the per cent of asphalt cement required in various classes of bituminous road construction ranges from 6 to 12. The average per cent of bitumen contained in samples of Alberta bituminous sand examined is about 15. Of this amount 15-17 per cent will be lost in necessary preliminary heating. On such a basis the bituminous content actually available in the anhydrous sand will thus be reduced to 12-18 per cent.” Some difficulty would be encountered in reducing the proportion of bitumen by the addition of sand. “If, however, the mixer used be furnished with sufficient power and the sand itself be preheated the desired reduction could doubtless be effected................ it appears that specially designed machines will have to be censtructed before Athabaska

“Before it can be successfully adapted to sheet asphalt work, the bitumen contained in the Alberta sand will require a very considerable modification. The

penetration of the extracted bitumen is much too high and constitutes the

dominant feature in considering its value as an asphalt cement. In the laboratory this feature can be sufficiently modified by proper heating and fluxing. Whether this will be found practicable when undertaken under conditions governing actual paving construction, can best be determined under conditions more nearly approaching those of commercial work.”

The “Preliminary report on the bituminous sands of northern Alberta,” from ‘which the foregoing information has been abstracted, contains detailed information regarding about eighty different outcrops, analyses, hints on prospecting, and other information of practical value.

During the ‘summer of 1915 some experiments! were conducted under the supervision of 'S. C. Ells of the Mines Branch, in the practical application of the _ bituminous sands‘ in street construction in the city of Edmonton.

Sane ee ee ae eee ee Pah a eS 1 Mines Branch, Dept. of Mines, Can., Sum. Rept., 1915, pp. 67-74,