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Rock asphalt was first mined at the top of Whitmore Canyon – 15 mi. NE of this location – in the early 1890’s. The mine closed in 1898 & re-opened in 1903. It operated erratically until 1915 when it was forced to close due to the development of sheet asphalt. In 1927 another Co. tried to develop a rock asphalt industry. They spent over 1/2 million dollars on equipment including a 3 1/2 mile gravity powered aerial tramway. To promote the use of rock asphalt for paving, it was sold for $8.00/ton even though production costs exceeded $16.00/ton. The Rock Asphalt Co. of Utah took over in 1932. The mine operated only about 2 months out of the year & eventually closed. Interest was rekindled in the 1970’s but nothing ever developed.

This marker is located at the Junction of Highway 6 and Highway 123.



Utah’s Asphalt Production Process Is One of Country’s Most Interesting

Sun Advocate – October 9, 1947

Every story of western mining carries with it a hint of romanticism and the spirit of adventure that cannot be found in any other industry in the world. The history of brave men with visions of the good that can be derived from the hidden treasures of nature has always been and probably will continue to be a source of inspiration to those whose walks of life have carried them into the other fields of endeavor. There is something of a mystery about mining, whether underground or above, and one can’t help but wonder at the strength of those who planned the industry into what it is today. Utah’s position as one of the leading states in the production of minerals is well know. Within its borders are found nearly every mineral of commercial importance. They hydrocarbon deposits of eastern Utah are enormous. Gilsonite and elaterite mines have been developed to a large extent and the products have been shipped to many parts of the world. Some of these hydrocarbons are perculiar, in that Utah is the only place in the world known where they are found. Among the many natural resources Utah has within its borders is the deposit of rock asphalt found east of Sunnyside. This deposit is the largest and richest of natural rock asphalt in the United States and, perhaps, in the world. There are many deposits of rock asphalt within the United States and several plants are now processing large tonnage from those deposits for use in street and road constuction.

The Utah deposit which is owned by the Rock Asphalt company of Utah is estimated to contain some 800 million tons. It is estimated that the deposit contains enough rock asphalt to build three 64 foot roads completely encircling the globe. The Sunnyside quarry is probably one of the most interesting in the country. Located 9,040 feet above sea level, the mineral is scooped out of the side of the mountain by huge shovels and is transported to the crushers in the valley eight miles away by means of huge buckets suspended on cables. The mountain in which the deposit is located is 10,000 feet high thus placing the diggings almost to the top. A private road leads to the mine winding up the mountain side and from there continues to top where, incidentally, is a deer hunter’s paradise. To have transported all of the heavy machinery to the quarry on the narrow road is an engineering fete within itself and is a source of wonder to the visitor.

Approximately 200 tons of rock asphalt are produced each nine hour working day from the present opening which ranges in thickness from 40 to 70 feet. Work is now going on to open a new face which is located several feet higher than the present working and which will open a vein ranging in thickness for 70 to 200 feet. The new section will also provide a much richer product. Initial tests have shown it to run at a minimum of 13 per cent bitumen. State specifications call for from 10 to 13 per cent bitumen with less than five per cent moisture content. To obtain the asphalt, holes are drilled in the face and powder is used to blast the mineral loose. It is then loaded into trucks for transportation to the dump where it is picked up by the buckets which carry it down the canyon. The cable carrying the buckets is approximately 14 miles in length, seven miles of carrying cable and seven miles of track cable. Sixty three buckets are in use with the loaded buckets pulling the empties back to the mine. Each bucket carries 1200 pounds of asphalt and the round trip for each bucket takes 1 1/2 hours. The mineral goes through a primary crusher before entering the buckets and is dumped into a storage bin at the bottom of the canyon. From here it is transported by trucks to the crusher at Sunnyside there it goes through two different sets of rolling mills before going through the final crushing process in a hammer mill. When the process has been completed the asphalt comes out of the mill in the form of powder as fine as flour. At this point it is loaded into railroad cars and trucks for distribution throughout the country. Each shipment is tested prior to distribution.

According to Eugene Pressett, superintendent of the Sunnyside operations, experiments are now being carried on by adding an oil emulsion to the crushed asphalt to develop a product that will withstand the lowest temperatures. Rock asphalt, or bituminous sandstone as it is commercially known, is a mixture of asphalt and sand compressed by nature into hard rock which was formed by liquid oil, with an asphalt base, accumulating underground in some kind of geological trap. The sand which was originally laid down as a marine sand of fine and uniform texture was then covered in this manner by a pool of asphaltic base oil, which, due to extreme underground heat and pressure, allowed the bolatile matter to escape leaving a residue of pure asphaltum permeating this stratum of marine sand. This was followed by additional natural formative pressure which caused the sand to be completely permeated by and coated with asphalt to an average of about 10 per cent asphaltum and 90 percent pure silics sand. These sand particles are not merely suspended in the asphalt but every void and pore of the sand is permeated with asphaltum so that a complete breakdown of one grain of sand would give an assay comparable to a larger or average piece of rock asphalt. Rock asphalt roads have been in use for many years. In fact, the first paved roads built in the world were of rock asphalt. History reports Paris built its first paved road of this material in 1854. The first paved street in the United States was built in 1872 in Union Square, New York City, of rock asphalt brought from Switzerland. The first street paved in Utah was old Commercial street in Salt Lake City and this was built in 1891 with rock asphalt brought from Santa Cruz, California. This started the development of the Utah deposits and in 1892 Richard street in Salt Lake City was paved with Utah rock asphalt and has been in continuous use for 17 years. The history of rock asphalt shows that it is the oldest known paving material and has been in continuous use since 1854. At the present time, work is being completed on the laying of asphalt on every street in Dragerton including the driveways into every yard. Approximately 8000 tons of the material has been used on this project.

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