Over the years many smelters have been found throughout the Uintah mountains. I do not believe that every one is of Spanish origin but there are a few that definitely are. A decent article was written on the topic by By Cristina Bailey, Tami Merkley and Byron Loosle and they discuss an important point that I have quoted below. The entire article is available here: http://www.fs.fed.us/r4/ashley/heritage/publications/myths-legends.pdf
"Several gold prospectors have indicated that a number of kilns found in the area were used by the Spanish to process the gold ore. This process would have produced great mounds of tailings, which at present nobody has located near these kiln sites. These kilns represent a case of cultural amnesia.
One of the most unconventional and unique stories in the Uintah Basin is the construction of the Bank of Vernal. In 1916 when the bank decided to move to the northeast corner of South Vernal Avenue and Main, they came up with a very creative way to ship the 80,000 bricks needed for the front of the building. Since the cost of freight was four times the cost of each brick, they decided to send them by parcel post at a cost of fifty-two cents for every fifty-pound parcel. The building became known as the “Parcel Post Bank”. The post office had to change its regulations in view of the incredible amount of work involved in the delivery of bricks and its low margin of profitability.
The brick for the bank could not be made locally. The bricks used on the frontispiece of the bank were textured, not like the regular bricks used to build homes. The need for regular bricks to build schools, commercial buildings and homes rapidly increased as Vernal kept growing. Kilns were necessary to manufacture bricks, process limestone for mortar, and plasters. Many brick making enterprises emerged in the late 1800’s and early 1900’s to provide the materials needed for construction.3
Robyn Watkins wrote an article about the limekilns in the Uintah Basin, documenting what remains of the old kilns in the region. Karl and Brig Swain were interviewed regarding their early 1900’s brick making operation. They described the construction and use of kilns in detail. After an extensive research, Watkins concluded:
Due to the evidence from local and historical descriptions of liming, slaking, and brick making, kiln locations on the Ashley such as Lime Kiln Springs and Dodd’s Hollow were limekilns and not Spanish gold smelters."3 Doris K. Burton, page 171.
Below are pictures I took 10 years ago of the two Lime Kiln Springs smelters that were discussed above.
There were several smelters built in the 1860's by early prospectors as well. These were typically of a beehive style as in the Delta (left photo) and Waterman Coking Ovens (40°25'47"N 112°17'14"W).
The typical construction back then was to build the kilns with parabolic domes, base diameters of 13 to 24 feet, and heights of 19 to 22 feet diameter with a hard white mortar. Another clue as to it being built by an early prospector was the use of 3 x 4-inch vents spaced about every three feet around the base of the kiln for regulating the fire (visible in the Delta kiln).
Most of the smelters I have seen in the Uintahs' were not that large, did not use vents or have white mortar, or any mortar at all that remained.
The following two pictures are smelters found along Farm Creek. With no history of lime smelting or any other type of mining in the area by early settlers, many believe these to be of Spanish origin. The first remains fairly intact, but the second was destroyed by either treasure hunters or fire fighters when the area burnt a few years ago.
Below is the Pole Creek smelter. Two others are found nearby and are also of the same construction as the Farm Creek smelters. Again there is no recent history of mining in this area, but there is plenty of evidence to indicate Spanish mined the Pole Creek area.
If the two smelter at Like Kiln Springs were early lime kilns and not of Spanish origin, then the Farm Creek and Pole Creek smelters could be made at the same time for similar purposes. Their construction is very similar in all three locations.
These two smelter (found in California and Nevada) are of Spanish origin but do not match those found in Utah or the description of Spanish smelters given in "De Re Metallica", the Spanish bible for mining and refining of ore from the late 1500's to the mid 1700's.
The California smelter is built up against a small ledge and have only these two constructed sides.
This Nevada smelter is square but has the typical stepped structure of Spanish smelters.
With so many different types of smelters constructed over the years, it is difficult to identify any as definitely of Spanish origin by their construction.