Abstract

The Whiterocks tar sand deposit is located near the mouth of Whiterocks Canyon, an important south drainage of the Uinta Mountains. This deposit is probably the least known and most unique of the major bitumen accumulations in the Uinta Basin. Historically, it is near the purported oldest white settlement in Utah and may have been the first tar sand to undergo minor development.

The Whiterocks deposit is contained in eolian sandstone of the Navajo Sandstone. The Navajo Sandstone is of Jurassic age and is equivalent to the Nugget Formation of Wyoming. The Navajo Sandstone at Whiterocks trends about S 60° W and dips 70° SE; its true thickness is nearly 1,000 feet. Bitumen saturation occurs in the highest 500–600 feet of the upended formation over a horizontal distance of at least 9,500 feet; the entire extent is undetermined. The saturated sandstone outcrops on the east and west sides of the Whiterocks River valley and is continuous beneath the alluvium.

The Navajo reservoir at Whiterocks is typically clean, well-consolidated, quartzose sandstone. There are a few shale and siltstone intervals and occasional limy zones although the formation is mainly non-calcareous. Fracturing is fairly common and some faulting is evident. The reservoir is divided into three vertical zones on the basis of barren and lean intervals. Porosities are in the range of 15 to 29 percent. Bitumen (or oil) content averages about 9.5 gallons per ton of ore.

Fourteen core and drill holes are described. No unusual technical problems are foreseen in the development of this important oil deposit.