The Shafter Mining District is an area in south central Presidio County in which are fifteen prospects that were mined for silver and related ores from 1883 until 1952. The district's boundary runs from the Chinati Mountains on the northwest to the flats of the Rio Grande on the southwest and to Cienega Mountain on the east. Most production came from one mine, the Presidio, in Section 8, Block 8, Houston and Texas Central Railway Company Survey, which produced over 32.6 million ounces of silver and 8,400 ounces of gold. The Presidio Mine resulted from several decades of exploration in the Chinati Mountains. In 1860 rancher John W. Spencer freighted several cartloads of silver ore to Mexico for smelting and received $20.50 a ton. Sixteen years later, in 1876, state geologist Samuel B. Buckley surveyed the Chinatis and found valuable ores of silver, lead, copper, zinc, mercury, and uranium. Buckley's ore samples were assayed with a silver content as high in value as $76.28 a ton and lead as high as $25.85 a ton. In 1879 Burr H. Duval traveled to Presidio County with a prospecting expedition of fifteen men that was organized by three railroads-the Galveston, Houston and San Antonio, the International-Great Northern, and the Texas and Pacific. Although Duval's party failed to find valuable minerals, they met and discussed prospects with two men who later figured in the development of the Shafter Mining District. They were Lt. John L. Bullis of the Twenty-fourth United States Infantry and Spencer, who had mined silver in the Chinatis nineteen years earlier.
Spencer crossed to the north side of the Rio Grande in 1848 and founded a ranch at Indio. After Fort Davis was established in 1854, he sold cattle and other goods to the military. In 1880, while on a freighting trip to Fort Davis, he discovered a surface rock that appeared to contain valuable minerals. He showed the sample to Col. William R. Shafter, who had it assayed. When the report showed a small amount of silver, Shafter took advantage of the discovery. He interested Lieutenant Bullis and another Fort Davis officer, Lt. Louis Wilhelmi, in a land deal on the acreage surrounding Spencer's strike. Although the partners bought four sections of land around the potential silver deposit, they lacked the capital and technical expertise to develop their prospect. In June 1882 they leased some of the acreage to San Francisco mining speculators who organized the Presidio Mining Company. The company soon found a silver deposit valued at $45 a ton and started the Presidio Mine there. Eventually the four partners sold their interests to Presidio Mining; each received 5,000 shares of company stock and $1,600 cash. The company hired 300 to 400 workmen and installed milling machinery.
By 1888 the Presidio Mine showed a profit. Between 1885 and 1912 it produced 450,000 tons of ore. The mill maintained a profitable average of 25.84 ounces of silver per ton with an 81.68 percent recovery. In 1913 the company introduced air drills to speed the mining of ore and replaced burro and mule drawn wagons with a tramway that hauled the ore from the mine in buckets, each of which held 500 pounds. A new and bigger cyanide-based mill replaced the old mercury-based one. With these improvements ore processing increased by more than 60 percent over that of the previous twenty-nine years, though the silver volume dropped to twelve ounces a ton. Higher silver prices and more efficient methods enabled the mine to make a profit. In 1926 the American Metal Company leased the Presidio Mining operations at Shafter with an option to buy, and the sale was finalized in 1928. Under the new management the mine's drifts and tunnels were extended to between 150 and 200 miles in length. Its annual production continued at a high level with a higher rate of silver recovery. The forecast appeared good until July 1930, when an acute downturn in the price of silver closed the mine.
When President Roosevelt announced a government policy to buy newly minted silver at 65½ cents an ounce, the Presidio Mine prepared to reopen on January 1, 1934. The reopened mine subsequently saw seven years of its highest production, but the quality of its ore steadily declined. By 1942 the ore gave up only 8.4 ounces of silver per ton. The mine closed in September 1942 because of the decline of the ore's silver content, diminished reserves, water flooding in the lower levels, and a wartime shortage of miners. In 1946 M. F. Drunzer leased the mine and gleaned the ore from the supporting pillars. He shipped more than 2,000 tons of ore, which held one ounce of gold, 1,056 pounds of copper, 29,368 pounds of lead, and 41,300 ounces of silver. The following year Drunzer shipped thirteen carloads of silver-lead ore. These final shipments ended work in the most extensive and longest-producing mine in Texas.
West of the Presidio Mine fourteen smaller mines and prospects operated in the Shafter District over the years. The Ross Mine, Section 9, Block 7, Houston and Texas Central Survey, was worked in 1890 and 1891. Lead-silver ore was mined, but little was shipped. The Chinati Mine, Section 2, Block 8, H&TC Survey, operated in 1890 and 1891 but shipped only one carload of lead-silver ore. In 1901 and 1902 the Chinati Mine and the nearby Montezuma Mine, Section 319, Block 7, H&TC Survey, were worked. The Chinati also ran a small smelting plant at Shafter, and ten carloads of lead bars were reportedly shipped. In 1915–16 the high wartime prices for zinc brought the reopening of these mines. In 1935 the Chinati was reopened and shipped 153 tons of lead-silver-gold ore. The Last Chance Mine, Section 14, Block 6, Galveston, Houston and San Antonio Railway Company Survey, opened in 1910 and shipped small amounts of lead-silver ore that year and in 1915 and 1916. In 1926 Harry Young reopened the mine and operated for about a year but shipped less than 30 tons of lead-silver ore. In the 1920s E. M. Gleim located a mine in Section 6, Block 8, H&TC Survey. The mine was worked intermittently and probably produced less than 100 tons of ore. In Section 6 at about the same time the Stauber Mine was dug to the Cibolo limestone in search of silver and lead. There is no evidence that the Stauber produced more than 100 tons of ore. In 1932 Dunham Perry developed a mine in Section 2, Block 8, H&TC Survey. Four carloads of ore with varying quantities of silver, zinc, lead, and gold were reportedly shipped to an El Paso smelter in 1933. Two other small mines were located in the western part of the district. They were the Sullivan Mine in Section 107, Block 7, H&TC Survey, and the Cibolo Mine in Section 14, Block 6, GH&SA Survey. The Sullivan produced more than 4,000 tons of low-grade lead-silver ore. The Cibolo Mine probably produced little valuable ore, but no production figures are available. At least five minor prospects were begun in the district. They were the MacDaniel, the Carr, the Red Hill, and two unnamed prospects. These produced less than 100 tons of low-grade ore each. The smaller mines and prospects reveal an abiding interest in small-scale prospecting in Presidio County. They were one-man or few-men operations that produced little commercial ore. None of the smaller mining efforts contributed substantially to the area's economy. However, the Presidio Mine made a significant economic contribution. At the time it closed, the mine employed 300 to 400 men and poured $60,000 monthly into the county economy. In the years the mine operated, the Presidio Mining Company was among the largest taxpayers in the county. More than 92 percent of the silver and 73 percent of the gold reported as produced in Texas came from Presidio Mine.
Several attempts have been made to reopen the Presidio Mine since 1950. Gold Fields Mining acquired the property in 1977 and new deposits of silver were discovered by 1982. Ownership then transferred to the Rio Grande Mining Company in 1994 and Silver Standard Resources, Inc. in 2001. The Canada-based Aurcana Corporation acquired the project in 2008 and completed construction of a new mine portal and a 24,000 square foot warehouse complex by 2012. However, mining operations were suspended indefinitely in 2013 following a sharp decline in silver prices.