A Mine With More Varieties Than Heinz Has Pickles
The Ingersoll Mine, Keystone, S.D.
By A.I. Johnson, Mining & Metallurgical Engineer
A few miles from Keystone, S.D., is a pegmatite mine which, since its discovery, has been a mecca for geologists and a paradise for rock hounds. Well over sixty separate minerals have been identified at the mine and, no doubt, more will be discovered. Some are of scientific interest only but a number have commercial value and several are both rare and valuable.
The Ingersoll Mine was originally discovered and located August 24, 1880, by John W. Okey, John Schofield and R.G. Williams. According to the location certificate it was situated “on Fairview Hill, east side of Poney Gulch, one and one half miles from the town of Sitting Bull, bounded…. on the South by Intersection and Independence Lodes…” It was named for Bob Ingersoll, at that time a well-known lawyer and politician noted for his agnostic views. Two other claims were located in the same group. The Horace Greeley was named for the popular editor and the Ben Butler was named for another lawyer who was a radical politician. (We don’t know the political or religious views of the locators.)
The group of the three mining claims was surveyed for patent in 1890 by Myron Willsie and the survey was filed April 17, 1891. The patent was issued and signed by President Grover Cleveland Dec. 4, 1894, “in the year of our Lord and of the Independence of the United States the one hundred and nineteenth.” In mining language a patent is the same as a warranty deed to the property. In the meantime, Harney Peak Tin Mining, Milling, and Manufacturing Co. had paid $155.00 in fees for the Ingersoll Group to George V. Ayres as Receiver in the United States Land Office at Rapid City and had full title.
The discovery of tin in the Black Hills in 1883 had created great interest in its possibilities, particularly in England because Cornwall was the world’s leading producer of tin, a position it had held for several hundred years, dating back to the Roman occupation. Prior to this some Black Hills tin had been identified as early as 1876 or 77. The Harney Peak Tin Mining, Milling and Manufacturing Co. was organized by a group of London and New York financiers and they undertook to monopolize the tin deposits of the Southern Hills. They were rported [sic] to have spent over ten million dollars in acquisition, exploration and development of over 1100 properties, including the Ingersoll Group. A hundred ton mill was built at the Etta Mine where there was a small town and post office named Etta, located near the present town of Keystone. At the Ingersoll a tunnel was driven 145 feet long to contact the tin deposit 120 feet below the surface but in 1889 an engineer, C.M. Vincent, engaged by English investors to make a report, stated that results were not encouraging but inferred that possibilities might be better at greater depth. A larger tin mill had been built in Hill City but because of the poor showing the Harney Peak Co. was forced into receivership in 1893 and all the properties were in litigation for many years.
The receivership was handled by the Pahasa Mining Co. which proceded [sic] with liquidation. On November 15, 1914, the Ingersoll Group and other properties were sold to Charles E. Kamman of Hill City. He leased the Ingersoll to Denis Henault. Henault was an enterprising Frenchman who had mining interests in the Northern Hills and who had served Custer County in the state legislature.
During Henault’s lease, tons of lithia ores, mica and beryl were shipped. One very large mass, approximately one ton, of columbite-tantalite, probably the largest single mass of that ore ever described at the Ingersoll, was shipped to Maywood Chemical Co. in New Jersey. Henault thought it was tin ore but when the true identification was made the shipment was discarded as there was no value for columbite-tantalite at that time. At present that tantalite content has reached from $80 to $100 per pound.
W.S. Dewing of Kalamazoo, Mich., owner of the “Kalamazoo Straight to You” Stove Co., had become interested through James “Big Hat” Clark in numerous other mining properties in the area. Dewing paid Kamman for the Ingersoll Group which was under lease to Henault and deeded one-half interest to Henault with a mortgage attached for that half interest in 1923. Dewing later, in 1930, foreclosed on the mortgage. His heirs-wife Caroline, daughter Winifred D. Wallace and her husband, William Kay Wallace of New York City, conveyed their rights to the Black Hills Keystone Corp. July 15, 1932. Eventual control of the corporation came to Wallace’s second wife, Karin Wallace, who lives in Monaco.
Harold Schafer, president of Gold Seal Glass Wax Co., bought the Ingersoll in May of 1980 and he has sold the property to U.S. Mining Co.
This property is a classic example of a coarse-grained pegmatite and has been studied by geologists from all over the world. Three principal pegmatite dikes are exposed. The mineral segregations are large enough to make possible hand sorting of the various kinds. The dikes usually consist of a quartz core with the different segregations extending outward to the walls of the dike which are most often schist or its modifications. The different minerals are separated according to their temperature gradient at the time of the formation of the dike. An intrusion of a viscous material contained all the minerals which, on cooling, became segregated from each other. For instance, we find a griessen zone, principally fine-grained mica, then coarser mica followed by a feldspar zone and, next to the core, are usually the rare minerals.
BERYL is one of the rare and valuable minerals occurring in the Ingersoll. Crystals of large dimensions always create great interest among mineralogists and geologists especially if the crystals are well-formed and free from foreign materials or of gem variety. Beryl crystals, whether large or small, are six-sided and vary in color from white to green. The emerald is a transparent phase of beryl. Sometimes beryl may be light shades of blue, yellow or rose.
About 1915 a large beryl crystal was exposed at the Ingersoll, a nearly perfect hexagon and white in color. It was 46 inches across the face, 44 ½ inches high and approximately 8 feet long. In 1933 the first large crystal was uncovered on Dike #2. It was 9 feet 8 inches high, slightly over 8 feet wide and produced 24 tons of beryl. In 1942 the second largest crystal was exposed on the same dike which was 19 feet long and tapered from 5 feet in width at one end to 19 inches at the other end. Dr. Hess, head of the Rare Minerals Division of the Bureau of Mines, visited the site and wanted to make a national monument of the formation but, because of the strategic importance of beryl in the war effort, the crystal was mined and sold.
In the fall of 1944 the largest beryl crystal yet uncovered was encountered in Dike #1 and measured 28 feet long with faces 8 feet 6 inches by 8 feet 8 inches in width. Over 64 ½ tons of beryl were recovered. Many smaller crystals have been mined through the years.
No specific use was known for beryl until Brush-Beryllium Co. of Cleveland, Ohio, developed a process of producing the metal beryllium from the beryl mineral. The problem of a brittle metal, easily shattered, has been overcome and a ductile metal was finally possible. The Brush-Beryllium Co. then needed a reliable source for the mineral and the Black Hills Keystone Corp. became a major producer. A 20 ton carload from the Ingersoll and Sitting Bull mines and an additional 43 tons from the Ingersoll were shipped in 1933 and another 11 ton shipment in 1934. Between 1933 and 1956 a total of 518 tons was shipped with the main production during the WWII years.
An unusual use by the government for the metal beryllium was as a moderator in the detonation of the atomic bomb. Another interesting use was in the nose of the space capsules because of the capacity of beryllium for quick absorption of heat and rapid dissipation of heat. Previously a use was found with copper. A small percentage acted as a hardening agent to make the copper as hard as steel. This copper alloy could be formed while still malleable, then heat-treated for hardening. This was thought to be a new process. However records show that the copper product found in excavations may have been used by ancient Egyptians, then becoming a lost art. Adding less than 1% beryl to feldspar furnishes a brilliance to ceramics, important in that industry. Beryllium has the unique property of strength associated with light weight.
Several lithia minerals of economic importance have been found at the mine. It has been one of the largest producers in the United States of LEPIDOLITE which is used principally in the glass industry. About 9000 tons have been mined and milled. It occurs in masses of flakes and hexagonal crystals up to ½ inch, in lilac and purple shades desired by decorators and collectors. It gives qualities to glass which make the glass less liable to breakage on sudden heating or cooling, produces a harder surface, makes the glass less brittle so it withstands shocks and vibrations, makes it more lustrous or brilliant, eliminates much corrosion in the manufacturing process and is a good opacifier. Two interesting uses of the Ingersoll lepidolite were in the making of Pyrex ware and in a lens for the observatory at Mt. Wilson, Cal., where its use allowed the huge 17 foot lens to cool slowly without warping.
At the mine it was hand sorted for a long time but larger reserves were developed and demand increased so a mill was built and began operation in July 1942, closing in September 1944 when foreign sources made production uneconomical. By-products of the lepidolite milling were mainly tin, tantalite-columbite, and microlite concentrate.
TIN, in the form of CASSITERITE, is found in lustrous black masses up to 100 pounds and smaller masses of granular structure have occurred. Some concentrates have been shipped as a by-product. ZIRCON, a sharp reddish brown crystal, has been found in the cassiterite. It fluoresces under ultraviolet radiation.
Also found with the lepidolite are gem varieties of TOURMALINE crystals. A pink tourmaline is known as RUBELLITE, the black as SCHORL, the brown as SODA DRAVITE, the greenish blue as INDICOLITE. They have specimen value.
MICROLITE, a calcium tantalate, was a by-product of the lepidolite process. Over a ton was shipped.
Occurring with lepidolite, but with unknown mineral associations, were the rare metals, CESIUM, STRONTIUM and RUBIDIUM in small quantities.
TANTALITE, a black heavy mineral, has been produced in the milling of lithia minerals. Usually it is associated with COLUMBITE which has very similar characteristics. World wide recognition has come to the Black Hills for the excellent specimens of tantalite-columbite, including those from the Ingersoll. Previously we mentioned the one tantalite mass shipped by Henault under the impression it was tin. Tantalum is used in surgical wire, sugical [sic] instruments and chemical ware, replacing platinum in many instances. It doesn’t corrode, is malleable. Columbium is used with steel to add toughness. One use is in the armor plate on battleships.
An exciting find during the mining for lepidolite was URANINITE, classified as PITCHBLENDE, a source of radium. Mme Curie separated radium from a mineral of this kind. A sample by Dr. Hess of the U.S. Bureau of Mines in Washington was used to make an age determination of the Black Hills. Results indicated the age of the Black Hills to be 1,620 million years, plus or minus 20 million years! In the superb solid masses up to 5 inches in diameter and 2 inches thick there were thick yellow or red alteration rims of AUTUNITE, URANOPHANE, KASOLITE, FOURMARIERITE, and VANDENDREISSCHEITE. 350 pounds was produced. Many unusual specimens were taken.
The mill at the Ingersoll for processing lepidolite and its by-products was the first and only one of its kind in the world.
The other two economic lithia minerals at the Ingersoll are AMBLYGONITE, a lithia aluminum phosphate, and SPODUMENE, a lithia aluminum silicate.
The largest mass of amblygonite was exposed at the top of pegmatite Dike #1. This developed to be 28 feet long, six feet in diameter. It was a vertical projection and it was necessary to sink a shaft through the mass to mine it. It occurred on the contact with the lepidolite zone. 1500 tons were produced and most of the amblygonite was shipped to Germany, going via Chicago and the Great Lakes.
Spodumene was in demand during WWII and nearly 200 tons were produced for Maywood Chemical Co. in New Jersey. It occurs in “logs” of hexagonal shape. White crystals 10 feet long, 2 to 3 feet wide were mined. CYMATOLITE, a white fibrous mineral is found in the crystals. With the spodumene are semi-precious gem varieties of green to yellow-green HIDDENITE, lilac-pink and bluish KUNZITE.
The strategic value of the lithium hydride produced from the spodumene was its use in inflating balloons or flares for signalling whereabouts of ejected aviators. Water added to the lithium hydride formed hydrogen gas which inflated the balloon. Lithium hydroxide is used in batteries and also in high grade grease. Lithium carbonate is used in ceramics. There are numerous medicinal uses now made of lithia products of spodumene. One is supposedly for reducing hypertension.
The most common economic minerals found at the Ingersoll are FELDSPAR and MICA. Very high grade quality of feldspar is found and among its many uses are those for dishes, bathroom fixtures and glazes. “Accent” on your kitchen shelf, to enhance the flavor of food, comes from soda feldspar. About 15,000 tons of feldspar have been shipped.
About 2200 tons of scrap mica have been produced. It is high grade and very white and is used in Christmas snow and in wallpaper. Some is used in paints and greases. Green tourmaline was found with this mica.
A by-product of the feldspar operation was some high quality WHITE QUARTZ, mostly used for decorative purposes.
Some of the minerals in the Ingersoll Mine have been depleted but diamond drilling by the Bureau of Mines indicates a considerable variety still in place. New methods and new uses may increase the value of the reserves in the future.
A.I. Johnson was the engineer in charge from 1933 to 1980 and was responsible for the geological surveying, mining methods, mill construction and processes.
To substantiate the claim of more varieties than Heinz a list is here appended of the identified mineral occurrences in addition to those discussed in the above paper:
- Brazilian emerald