Kabba
History
On the western edge of the Kabba prospect, where the Hualapai Mountains rise above valley-filling sand and gravel, a very large Laramide-age porphyry Mo/Cu deposit crops out. This porphyry intrusion, measuring 12 miles long by 1.5 miles wide, has been thoroughly explored by the likes of Bear Creek Exploration Company, Union Carbide Corporation, AMAX, Cerromin, Conoco, Hanna, Kerr-McGee, Santa Fe, and Noranda. The efforts of these companies demonstrated the intense alteration, quartz veining, and highly anomalous molybdenum and copper contents typical of major porphyry copper deposits, but the basis for a money-making mining operation was never established.
The known, outcropping parts of this porphyry copper system appear to be an exposure of a deep level of the original porphyry system, deeper than where the richest deposits of copper would be expected. A major fault located on the west edge of the Kabba prospect separates this deep porphyry exposure from a down-dropped block that may contain the richer copper-bearing parts of this porphyry system, directly underneath the Kabba prospect. A 1974 Master's thesis by John Vuich, studying under John Guilbert at the University of Arizona, surmised that the richer top of the deposit was most likely still present in the subsurface east of the outcropping part. During the 1960's - 1970's, the major mining companies focused on exploring near-surface deposits, and the idea slowly sunk below the radar screens of the big Arizona mining companies...
As with diamondiferous kimberlites, porphyry copper deposits erode at the earth's surface to disperse a plume of distinctive heavy indicator minerals leading down slope from their source. Review of government records showed that vanadium-molybdenum mining had taken place in the earliest 1900's at a site six miles east of the known porphyry copper system. Previous mining at this site during the early twentieth century produced small quantities of vanadium-molybdenum ore with gold and lead credits.
A small erosional window through thin pediment cover surrounding the Kabba Mine reveals mineralized and hydrothermally altered bedrock intruded by porphyry dikes and sills. Systematic sampling of sandy ravine bottoms in the area defined a prominent plume of heavy minerals comprising gold, scheelite (tungsten), rutile (titanium), wulfenite, fluorite, barite, and pyrite streaming eastward from an unknown source.
These heavy minerals are believed to be indications of the outer mineralized fringes of the shallower parts of a major porphyry copper system located somewhere under the Kabba prospect area.