Mines, Men, and Minerals - An Update on Mineral Collecting in The Hansonburg District
By Michael R. Sanders and Thomas M. Massis
The Hansonburg Mining District is located on the west side of the Sierra Oscura Mountains in central New Mexico. It lies about 55 km. southeast of Socorro at the northern boundaries of the White Sands Missile Range. The district includes the Blanchard, Mex-Tex, Royal Flush, and Rose mines, with additional short tunnels and open-cut areas that lie 3-8 km. south of New Mexico Highway 380 and the village of Bingham. Mining has occurred in the district since the 1880s, with the main ores of interest being fluorite, barite, and galena. Mineralization occurs as veins in steep westerly-dipping fault structures and in highly fractured and silcified, sub-horizontal Pennsylvanian-age limestones that lie immediately adjacent to the faults. Veins and adjacent mineralized rock often contain substantial open spaces and crystal-lined vugs that are exposed both in open cuts and trenches on the surface and in mine tunnels.
The Hansonburg district, in particular the Blanchard, Mex-Tex, and Royal Flush mines, have become widely known as a source of fine crystal specimens for the past 40 years or so. However, commercial mining operations conducted prior to control of the claims by the current claimants were geared almost exclusively to the production of ore. Surprisingly few specimens were salvaged from pre-1960s mining operations. We can only speculate as to the quantity and quality of the fine mineral specimens that were sacrificed to the crusher during the course of commercial mining in the district. However, we must conclude that the loss of irreplaceable material must have been substantial, given the quality and quantity of specimens currently being produced from the existing tunnels and excavations at these properties. All of the mineralized areas accessible to claiming are currently under the control of claimants, whose sole interest is the production of mineral specimens. Some of the properties are accessible to the general public for fee collecting or by appointment.
We decided several years ago to increase the scale of specimen production at various locations within the district. Prior to this time, we had used only hand tools and occasional digging and blasting to produce material. We decided to try a somewhat larger mechanized operation and used a tracked Caterpillar 320L excavator in conjunction with hand-digging to recover specimens. This increase in scale has proved successful (some years we even made expenses!), and the machine has been used for the last four years to excavate mineralized areas exposed in existing surface open cuts. The operation has taken place around Memorial day of each year and has lasted about 10 days each time. Limited specimen extraction with hand tools has also taken place in some of the underground workings at these properties.
Many different minerals have been produced from the Blanchard, Mex-Tex, and Rose mines. At the Mex-Tex mine, we found high-quality, rare secondary minerals and some of the more common species. This included brochantite, crandallite, creedite, cyanotrichite, libethenite, linarite, murdochite on smoky quartz, plumbogummite, pseudomalachite, spangolite, and tsumebite. The spangolite (crystals up to 3mm.in length) and cyanotrichite specimens are among the best ever found in New Mexico. Fine clusters and groups of both amethystine and smoky quartz (some liberally sprinkled with micro murdochite crystals) have also been produced from the Mex-Tex mine. Specimens of fine sky-blue fluorite crystal groups with barite blades have come from the Rose mine. Also, a large pocket at the Royal Flush mine produced in excess of 4,000 of specimens with small, but gemmy fluorite crystals on matrix.
The operations at the Blanchard mine have also been productive and successful. Sky blue, purple, and pale green fluorite crystals up to 7 cm. on an edge, in mainly the cubic to modified cubic habit, but also in the hexoctahedral and dodecahedral habits, have been produced throughout the Blanchard mine area. Fluorite and barite specimens sprinkled with small (up to 2 mm.) butterscotch-yellow wulfenite crystals were found near a large wooden ore bin on the property. A large crystallized cavity was discovered in one of the “Sunshine” tunnels in 1996, and much of the ceiling proved to be coated with dark blue fluorite and highly altered galena crystals to 5 cm. on an edge, along with barite. Fortunately, almost all of the crystallized material was attached to a 15-cm. thick layer of silicified limestone that had either already gently slumped to the floor of the cavity or was partially detached and, therefore, easily removed. As a result, almost all of the crystal specimens were recovered with very little to no damage, a very unusual and fortuitous set of circumstances indeed! The New Mexico Museum of Natural History and Science purchased most of the larger specimens from this cavity, and the Museum plans to use this beautiful material for a crystal cavity wall reconstruction at the museum. We are most gratified that this New Mexico treasure will remain in New Mexico. Water-clear, color-zoned fluorite cubes to 4 mm. with hexoctahedral modifications were also found in this same pocket.
Other minerals produced from the various Blanchard mine tunnels and surface workings include linarite and brochantite, in association with fluorite, and beige-colored bubbly smithsonite. A very fine, large cabinet-sized specimen consisting of blue fluorite cubes to 5 cm. nested within large lustrous cream-colored barite crystals to 16 cm. was, after much careful and skillful effort, recovered with very little damage from another Sunshine tunnel. This exceptional specimen passed through several mineral dealers hands, and it was ultimately purchased by the New Mexico Bureau of Mines and Mineral Resources mineral museum in Socorro, where it is now on display.
Finally, one of us (Mike Sanders) has been working on geologic mapping of the main tunnels at the Blanchard mine, in order to determine how the mineralized zones exposed in each of the tunnels are connected to each other, both horizontally and vertically. The Sunshine Mining Company of Boise, Idaho conducted a large-scale exploration project at the Blanchard mine from 1958 to 1960, and they excavated most of the tunnels at the property. As part of this study, the Sunshine Mining Company was contacted to determine if they retained any maps, reports, and other information that was undoubtedly generated during this project, and whether such information, if it still existed, could be released to the current claimant. The Sunshine Mining officials contacted regarding this project had no recollection of it, but they graciously allowed us to search through their archived data stored in northern Idaho. A trip was made to Idaho to search the archives, and some plan and cross section maps produced during their project were found. The Sunshine Mining Company again generously allowed copying any of the information that was considered of interest.
This historical Sunshine Mining data will be used in conjunction with
the ongoing geological study to help determine the amount of potentially
productive mineralized ground that remains at the Blanchard mine. If (1)
reserves prove sufficient, and (2) if it appears that a sufficient quantity
and quality of mineral specimens can be produced from those reserves to
support an economically viable mining operation, and (3) if the cost of
other safety and logistical issues can be overcome, then underground specimen
mining may at some point take place at the Blanchard mine.