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Rifle Mills (Old and New)
Location: The Rifle (Old and New) Mill sites are located near the town of Rifle in Garfield County, Colorado.
Background: The Old Rifle mill was situated on a 24-acre parcel on the north side of the Colorado River about 0.3 miles east of Rifle, Colorado. The plant was built by the Standard Chemical Company in 1924 and operated until 1928. In the early 1920s the domestic radium industry collapsed, and domestic uranium-vanadium ores were treated mainly for vanadium recovery. The uranium values were discharged along with the mill tailings. The United States Vanadium Company purchased the Rifle plant in 1928 and used it to recover vanadium from roscoelite ore until 1932, when an ore shortage forced its closing. In 1942, Union Carbide Corporation (UCC, which had acquired U.S. Vanadium and the mill) reactivated the mill for vanadium production in support of the war effort. In 1947, the Atomic Energy Commission signed the first of four contracts with UCC for uranium procurement, and the milling process was modified to allow recovery of uranium and vanadium by a sulphuric and hydrochloric-acid leaching process. From October 1947-December 1957, the Old mill processed ore at about 200 tons of ore per day (TPD) and treated nearly 0.7 million tons ore averaging 0.35 percent U3O8 and 1.59 percent V2O5. The mill’s raw ore feed came mainly from company-controlled mines and independent miners in western Colorado. Old vanadium tailings remaining on the site from earlier operations were reprocessed at the mill to recover uranium and residual vanadium. From the combined mill feed materials (ore and tailings), uranium recovery averaged 85 percent and vanadium averaged 69 percent. The AEC purchased all U3O8 produced and 27 percent of the V2O5 during the AEC-contracts period (1947-1957). Of the 0.7 million tons of tailings generated during the AEC uranium contracts period, about 0.4 million tons eventually were moved to the New Rifle mill and reprocessed for uranium and vanadium. The remaining tailings pile, about 0.3 million tons, stood about 33 feet tall and covered 13 acres at the old mill site. In 1967, UCC stabilized the tailings pile in accordance with the State of Colorado regulations. At that time, the pile was reshaped, covered with a 6-inch layer of soil, and seeded with native grasses. The Old Rifle Mill continued to operate during the period of construction of the New Rifle Mill.
The New Rifle Mill was built on a 300-acre parcel located about 2 miles west of Rifle just north of the Colorado River. It began operation in January 1958 at a nominal capacity of 400 TPD. Mill feed consisted primarily of ore from both company-controlled mines and independent miners in western Colorado plus uranium concentrate (slimes and chemical precipitates) from UCC's upgrader plants located at Slick Rock, Colorado, and Green River, Utah (1957-1961), lignite-ash product from the Belfield, North Dakota, ashing facility (1965-1967), and other tailings and residue materials. The new Mill produced uranium concentrate for sale to the AEC through December 1970. During the period of AEC contracts, the mill averaged 400 TPD throughput and treated a total of 1.8 million tons of ore that contained 8.4 million pounds U3O8 and 76.7 million pounds V2O5. Other mill feed, upgrader ore concentrates, lignite ash, tailings, and residues, contained an additional 4.5 million pounds U3O8 and 65.4 million pounds V2O5. Over the years 1958-1970, recovery from the combined mill feed averaged 90 percent or uranium and 83 percent for vanadium. About 96 percent of the uranium concentrate from the mill was purchased by the AEC. All of the mill's vanadium production was delivered to the commercial market. At the termination of UCC's last AEC-procurement contract (December 1970), there were about 2.5 million tons of tailings impounded at the New Rifle Mill site. The mill continued to produce uranium during 1971 and 1972 for the commercial market. At that time, the tailings pile at the new mill site contained about 2.7 million tons of tailings in two piles that covered an area of about 32 acres and stood about 65 feet above the surrounding site. From 1973-1984, the vanadium circuit at the mill was used to treat vanadium solutions trucked from UCC's mill at Uravan, Colorado. This vanadium recovery operation did not result in the addition of tailings to the existing tailings pile. Prior to 1982, UCC had covered the tailings piles with soil and had seeded, fertilized, and irrigated them to stabilize the steep slopes by establishing a vegetative cover. This was only partly successful, and the piles eventually were impacted by wind and water erosion.
Background: The Old Rifle mill was situated on a 24-acre parcel on the north side of the Colorado River about 0.3 miles east of Rifle, Colorado. The plant was built by the Standard Chemical Company in 1924 and operated until 1928. In the early 1920s the domestic radium industry collapsed, and domestic uranium-vanadium ores were treated mainly for vanadium recovery. The uranium values were discharged along with the mill tailings. The United States Vanadium Company purchased the Rifle plant in 1928 and used it to recover vanadium from roscoelite ore until 1932, when an ore shortage forced its closing. In 1942, Union Carbide Corporation (UCC, which had acquired U.S. Vanadium and the mill) reactivated the mill for vanadium production in support of the war effort. In 1947, the Atomic Energy Commission signed the first of four contracts with UCC for uranium procurement, and the milling process was modified to allow recovery of uranium and vanadium by a sulphuric and hydrochloric-acid leaching process. From October 1947-December 1957, the Old mill processed ore at about 200 tons of ore per day (TPD) and treated nearly 0.7 million tons ore averaging 0.35 percent U3O8 and 1.59 percent V2O5. The mill’s raw ore feed came mainly from company-controlled mines and independent miners in western Colorado. Old vanadium tailings remaining on the site from earlier operations were reprocessed at the mill to recover uranium and residual vanadium. From the combined mill feed materials (ore and tailings), uranium recovery averaged 85 percent and vanadium averaged 69 percent. The AEC purchased all U3O8 produced and 27 percent of the V2O5 during the AEC-contracts period (1947-1957). Of the 0.7 million tons of tailings generated during the AEC uranium contracts period, about 0.4 million tons eventually were moved to the New Rifle mill and reprocessed for uranium and vanadium. The remaining tailings pile, about 0.3 million tons, stood about 33 feet tall and covered 13 acres at the old mill site. In 1967, UCC stabilized the tailings pile in accordance with the State of Colorado regulations. At that time, the pile was reshaped, covered with a 6-inch layer of soil, and seeded with native grasses. The Old Rifle Mill continued to operate during the period of construction of the New Rifle Mill.
The New Rifle Mill was built on a 300-acre parcel located about 2 miles west of Rifle just north of the Colorado River. It began operation in January 1958 at a nominal capacity of 400 TPD. Mill feed consisted primarily of ore from both company-controlled mines and independent miners in western Colorado plus uranium concentrate (slimes and chemical precipitates) from UCC's upgrader plants located at Slick Rock, Colorado, and Green River, Utah (1957-1961), lignite-ash product from the Belfield, North Dakota, ashing facility (1965-1967), and other tailings and residue materials. The new Mill produced uranium concentrate for sale to the AEC through December 1970. During the period of AEC contracts, the mill averaged 400 TPD throughput and treated a total of 1.8 million tons of ore that contained 8.4 million pounds U3O8 and 76.7 million pounds V2O5. Other mill feed, upgrader ore concentrates, lignite ash, tailings, and residues, contained an additional 4.5 million pounds U3O8 and 65.4 million pounds V2O5. Over the years 1958-1970, recovery from the combined mill feed averaged 90 percent or uranium and 83 percent for vanadium. About 96 percent of the uranium concentrate from the mill was purchased by the AEC. All of the mill's vanadium production was delivered to the commercial market. At the termination of UCC's last AEC-procurement contract (December 1970), there were about 2.5 million tons of tailings impounded at the New Rifle Mill site. The mill continued to produce uranium during 1971 and 1972 for the commercial market. At that time, the tailings pile at the new mill site contained about 2.7 million tons of tailings in two piles that covered an area of about 32 acres and stood about 65 feet above the surrounding site. From 1973-1984, the vanadium circuit at the mill was used to treat vanadium solutions trucked from UCC's mill at Uravan, Colorado. This vanadium recovery operation did not result in the addition of tailings to the existing tailings pile. Prior to 1982, UCC had covered the tailings piles with soil and had seeded, fertilized, and irrigated them to stabilize the steep slopes by establishing a vegetative cover. This was only partly successful, and the piles eventually were impacted by wind and water erosion.
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