GRAND CANYON MINING: ORPHAN MINE & HALOTRICHITE

Writing a blog posing is like dropping a rose petal down the Grand Canyon and waiting for the echo.       Apologies to Dan Marquois
 

The November 19, 2019, posting described minerals, especially philipsbornite and osarizawaite, collected from the Grandview Mine located on Horseshoe Mesa within Grand Canyon National Park (GCNP).  The Mine had a long history of producing copper, and attracting visitors, until purchased and annexed into the Park in 1940.  Specimens continued to appear from the Mine (collected illegally) until “bat gates” closed the entrance in 2009.

I have now acquired a second specimen, halotrichite (originally in the collection of David Shannon, noted Arizona rockhound), collected from a mine near Grand Canyon Village in the Park—the Orphan (Lost Orphan; Orphan Lode) Mine.  I am indebted to George Munford of Northern Arizona University for the information in the paragraph below.  See George’s complete story at intermountainhistories.org.

 

Hogan built the Hummingbird Trail down to the mine entrance--not for me.  Photo Public Domain courtesy of GCNP.

The Mine was originally staked as a copper prospect by Danial Hogan (maybe with Henry Ward as a partner?) in 1893 and then Hogan upped the ante by filing a patented claim with Charles Babbitt in 1906.  The Mine was never a large copper producer and continued to struggle in the early 1900s.  This struggle was compound in 1919 when the Mine was incorporated into the new National Park.  By the late 1930s Hogan saw a new opportunity for his land and invested in building the Kachina Lodge for tourists. But more troubles hit Hogan as World War II essentially stopped the flow of visitors to the Park.  He ended up holding onto the claim until finally selling it in 1946, without ever hitting the big bonanza.  The new owners (several of them) continued struggling until rich uranium ore was discovered in 1951. “Big Mining companies” then moved in with money, purchased the claim, started mining, and greatly expanded the business during the “cold war” and uranium boom. Western Gold and Uranium, Inc. (the owners) built a tramway from the south canyon rim down 1800 feet where the Mine entered the side of the canyon wall.  Ore was transported up to the rim and then hauled to a processing plant in Tuba City, AZ. On May 28, 1962, President John Kennedy signed into law, Public Law 87-457, which permitted Western Equities, Inc. to mine uranium ore in Grand Canyon National Park, adjacent to the Orphan claim, in exchange for title to the claim in 25 years (1987) . The law specified that all mining would be underground and that the tram would be dismantled by 1964. The Federal Government would receive a royalty ranging from 5 to 10 percent on the ore produced (Chenoweth, 1986).  The tram was dismantled, and a 1500 foot shaft was drilled straight down from the rim and an elevator was installed.

 

Headframe of the Orphan Mine on rim of Canyon.  Photo Public Domain and courtesy of GCNP.

The tramway ran from the rim to the mine, 1800 feet of cable.  Book may be ordered from Grandcanyonorphan.com

For those of us in Colorado it is interesting to note that in 1967 the Orphan claim and related properties were sold to the Cotter Corporation of Roswell, New Mexico, and Canon City, Colorado. During 1967, the Cotter Corporation enlarged its mill at Canon City to process 400 tons per day in an alkaline leaching circuit and 100 tons per day in an acid circuit. A flotation cell was added to remove iron and copper sulfide minerals from the ore prior to alkaline leaching. The first ore was loaded for Canon City on rail cars at an Atchison, Topeka and Santa Fe Railway Company's siding in Grand Canyon National Park on September 27, 1967. Since Cotter's AEC contract had expired on February 28, 1965, all uranium produced after that date was sold on the private market to electrical utilities (Albrethsen and others, 1982).

By 1969 the mine had produced nearly 500,000, tons of ore that yielded about 4.2 million pounds of uranium oxide. By then Mine owners were going bankrupt due to rising production and transportation costs, and federal regulations. The National Park Service finally acquired the abandoned mine and surrounding acres in 1987.

As with many mines in the West, bankrupt owners left U.S. taxpayers a cleanup bill.  The Orphan Mine was declared a Superfund Site due to contamination by the uranium and we shelled out 15 million bucks to remediate the site.  Even today uranium mining companies want to mine near the Park and a wide variety of groups and citizens continue to fight this proposition.  In 2012, the Secretary of the Interior issued a 20-year temporary ban on exploration for new uranium mines (currently 831 active mining claims) on one million acres of public lands surrounding the Grand Canyon National Park.   Rep. Raúl Grijalva (R-AZ) introduced the Grand Canyon Centennial Protection Act to ban new uranium mines around Grand Canyon National Park forever. The bill passed the U.S. House of Representatives on October 30, 2019.  On December 19, 2019, Sen. Kyrsten (D-AZ) introduced a companion bill, S-3127, in the U.S. Senate; it is awaiting action.

 

Mining the breccia pipe.  Sketch courtesy of Chenoweth, 1986.

Early reports on the Orphan Mine by Max G. Kofford, chief mine geologist for Golden Crown and Western Gold and Uranium, attributed its origin to a cryptovolcanic structure or diatreme. However, as with the Grandview Mine previously described, the minerals at the Orphan Mine are concentrated in breccia zones situated alongside structural flexing features.  The ore bodies are a pipe-like structures entirely hosted in the upper Redwall Limestone and are associated with the Breccia Pipe Uranium District described by Wenrich and others (1992, 2018).  They noted  “the northern Arizona metallic district can be thought of as a paleo-karst terrain, pock-marked with sink holes, where in this case most “holes” represent a collapse feature that has bottomed out over 3000 ft (850 m) below the surface in the underlying Mississippian Redwall Limestone. These breccia pipes are vertical pipes that formed when the Paleozoic layers of sandstone, shale and limestone collapsed downward into underlying caverns.”  The base-metal ores (copper and silver) may be related to, or similar to, Mississippi Valley Type deposits where emplacement of ores suggest low temperatures (as opposed to hydrothermal emplacement).  Perhaps even more interesting in today’s geopolitical world is that Rare Earth Elements (REEs), and especially Heavy Rare Earth Elements (HREEs), are significantly enriched in the uraninite (UO₂) found in many breccia pipes.  “Mixing of oxidizing groundwaters from overlying sandstones with reducing brines that had entered the pipes due to dewatering of the Mississippian limestone created the uranium deposits” (Weinrich and others, 2018).  I wonder if REEs are also present at the Orphan?

Halotrichite crystals/fibers on matrix.  Width FOV ~9 mm.  I remain uncertain about the golden/yellow grains and the black grains; they may be some of the uranium minerals.

So, the lonely mineral I have from the Orphan is halotrichite, a hydrated iron aluminum sulfate [FeAl₂(SO₄)₄-22H₂O]. The mineral is interesting in that it usually appears as acicular or hair-like fibers that may form tuffs, matted crust-like aggregates, or efflorescence.  The colors are usually pastels-white, colorless yellowish, greenish and crystals are quite soft at ~1.5 (Mohs).  They have sort of a silky luster and are water soluble. Halotrichite may precipitate around hot springs and volcanic fumaroles or form as efflorescence in weathering sulfide deposits and oxidizing pyritic coals.

REFERENCES CITED

Albrethsen, Holger, Jr. and F. A. McGinley, 1982, Summary history of domestic procurement under U.S. Atomic Energy Commission contracts, final report: U.S. Department of Energy, Open File Report GJBX-220(82).

Chenoweth, W.L.,1986, The Orphan Lode mine, Grand Canyon, Arizona, a case history of a mineralized collapse-breccia pipe: USGS Open File Report 86-510.

Weinrich, K. J., G.H. Billingsley, and B.S. van Gosen, 1992, The potential of breccia pipes in Mohawk Canyon area, Hualapai Indian Reservation, Arizona: U.S. Geological Survey Bulletin 1683-D.

Weinrich, K.J., P. Lach, and M. Cuney, 2018, Rare-Earth elements in uraninite-Breccia Pipe Uranium District Northern Arizona in Delventhal, E. (ed), Minerals from the metallic ore deposits of the American Southwest symposium: Friends of Mineralogy-Colorado Chapter.

A LITTLE TIDBIT

In the late 1950s, the mining company believed the uranium lode extended beyond their claim into federal property.  In what appears to be some muscle, the company proposed building an 18 story, 800 room hotel overhanging the rim. This grand hotel would spill “down the side of the precipitous cliff like a concrete waterfall” ending at a swimming pool and sun deck below.  The mining company thought that the public would much better like a small uranium mine in their Park rather than a giant hotel.  Put some pressure on the Park Service!!  The compromise was the 1962 Kennedy Law with the hotel taken off the drawing board.  Photo above courtesy of GCNP. 

Not all holes, or games, are created equal.   George Will