February 2010

Economic Geology

Poryphry deposits (Part 3)

By R. J. Cathro

 

 A wide-angle view of the Bingham Canyon Mine, situated on “The Hill” at the junction of Bingham Creek (left) and Carr Fork (right), ca. 1908. Stripping of overburden and leached cap is well advanced on the Utah Copper property at the bottom of the hill; stripping has also started on the Boston Consolidated property near the top of the hill (from USGS Professional Paper 111, 1920).


“At no point on the globe are there developments of greater importance, or that are likely to have a more profound effect on the future of the copper industry. It is not beyond the bounds of possibility that the Utah Copper Company is the pioneer in solving the question of the world’s future copper supply.”

~Stevens, 1907

Between 1900, when Samuel Newhouse obtained British financing for The Boston Consolidated Mining Company (the American subsidiary), and 1910, when it was taken over by the Utah Copper Company (UCC), the two companies competed vigorously to control the Bingham  Canyon porphyry copper deposit. It was a struggle that Boston Consolidated should have won because it held the better land position. However, the outcome helped establish the reputation of Daniel Jackling as “the father of the porphyries.”

Before moving to Republic, Washington, in 1900 to build a cyanide mill for Canadian interests headed by Clarence McCuaig, Daniel Jackling had established a reputation as a metallurgical engineer who specialized in cyanide milling at gold mines. While working for Joseph De Lamar at Mercur, he had been given an opportunity to join, as a junior member responsible for the mill tests, the engineering team that investigated the feasibility of developing Enos Wall’s Bingham copper property. His exposure to the senior members of that team and to the new mineral deposit model at Bingham enabled him to see that the future of copper mining would depend on scale of production, surface mining, and mechanization rather than on grade alone. That experience made a profound and lasting impact on his life.

Daniel Cowan Jackling’s early rise from an impoverished background reads like a character in a Horatio Alger novel. He was born on a farm at Appleton, Missouri, in 1869, was orphaned two years later, and was raised on farms by relatives who, fortunately, recognized his intelligence and made sure he received an education. He graduated from the state Normal School and went on to complete a science degree in 1892 at the Missouri School of Mines, at Rolla. After teaching for a year at the School of Mines, he spent three years working as a miner, assayer, mill hand and metallurgist, mainly in the Cripple Creek camp in Colorado, where he met the Charles MacNeill group. His next assignment took him to Mercur, Utah, where he became construction and metallurgical superintendent for De Lamar at the Golden Gate Mine, which operated the largest cyanide gold mill in America.

When he left Republic in 1901, he returned to Colorado to become a consultant to MacNeill’s United States Reduction and Smelting Company, which operated two mills at Colorado City that treated ore from mines at Cripple Creek. That gave him the opportunity to describe his ideas about Bingham to them. With their encouragement, he returned to Utah, and with the assistance of Hartwig Cohen, De Lamar’s former general manager, was able to secure an option from Wall by mid-1903. This led to another crucial examination of Wall’s property by a team composed of MacNeill, Spencer Penrose, his brother R.A.F. Penrose (a distinguished geologist) and Jackling, and then another detailed sampling program by consultant F.H. Minard.

Minard reported that weathering of the sulphide zone had resulted in a surface zone of leaching about 15 metres thick with an average grade of about 0.75% Cu. It was underlain by a zone of chalcocite enrichment about 30 to 50 metres thick that averaged about 2% Cu, which was underlain, in turn, by unaltered primary ore averaging about 1.1% Cu. He estimated that the reserves of the enriched zone outlined to date totalled approximately 8,150,000 tonnes at an average grade of about 1.6% Cu.

That was good enough for the MacNeill group, which organized Utah Copper Company in June 19 03. Jackling was given 50,000 shares, which he shared with Cohen. The new company acquired all but 20 per cent of Wall’s 75 per cent interest in the property for $420,000 and De Lamar’s 25 per cent interest for $125,000 — a total price of $545,000. De Lamar, who had made the safe and sensible decision not to invest in the project, missed out on a fortune. However, when he died in New York on December 1, 1918 at the age of 75, his obituary in the Times claimed that he had made more than $20 million in Western mining. It also noted that he was president of the Dome Mine Company in Porcupine, Ontario, and vice-president of the International Nickel Company.

UCC raised about $750,000 through the sale of bonds to its Colorado backers, which provided enough money to construct a 270 tonne-per-day test mill at Copperton, at the mouth of the canyon. It was designed to verify the accuracy of the mine sampling, to determine the rates of recovery at a larger scale, and to test various crushing and concentrating devices. Jackling quickly assembled a team of former milling associates from Mercur and second-hand equipment from Colorado, and had the test mill operational by April 1904. However, UCC still lacked enough capital to construct the large project that Jackling envisaged, including a steamshovel stripping operation, so the mine had to be initially prepared for underground stoping.

Jackling now began to show the strength of his personality by enlisting the financial support of Daniel Guggenheim of Guggenheim Exploration Co. and American Smelting & Refining Co. (ASARCO). This was a family enterprise started by the patriarch, Meyer Guggenheim, who had established prosperous lace, embroidery and wholesale grocery businesses in Philadelphia after immigrating in 1848. In 1879, following an urge to find something bigger for his seven sons to participate in, he bought a half-interest in a silver mine at Leadville, Colorado. After a bonanza lode was discovered, the family then invested in a lead smelter at Pueblo, Colorado, which they gradually leveraged into a vast enterprise. In the period between 1906 and 1912, the words Guggenheim and copper were to become almost synonymous.

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