Circular 105—Evaluation of ground mica products from New Mexico pegmatites

By W. E. Horst and R. B. Bhappu, 1969, 27 pp., 11 tables, 2 figs., 1 appendix.

In accordance with the primary objective of the NM Bureau of Mines and Mineral Resources to assist in developing the mineral resources of New Mexico, an investigation was made to demonstrate that ground-mica products of commercial quality could be produced from potential raw material sources in NM. Samples from several local sources of mica in San Miguel and Rio Arriba Counties and one sample of sericite from Valencia County were obtained for processing and subsequent evaluation in the laboratory at Socorro. Various grades of dry- and wet-ground mica products were made from each raw materials sample, as well as measurements pertaining to the physical properties of the finished mica products for comparison with commercial quality products.

Results of the development project showed that the mica and sericite examined from local sources appear to be satisfactory for manufacturing commercial grades of ground-mica products. One of the mica-bearing samples was found to be inferior for making ground-mica products when color is an important physical property. Products made from this particular sample were off-color, being light tan compared with the white colored products made from other mica samples. Other mica-bearing deposits throughout New Mexico would require evaluation to determine the most outstanding local sources of mica based on ground-mica product quality and the economic value of the potential ore deposit.

Consumption of ground-mica products is closely related to the status of the building industry and fluctuates accordingly. Current consumption of ground-mica products is about 100,000 tons a year with a total product value of almost six million dollars annually. Recent investigations at the NM Bureau of Mines and Mineral Resources have shown that most of the NM micas evaluated are equal or superior to existing commercial products. The current mica production in NM is very small; however, it is reasonable to believe that mica production for the ground-mica markets could be significantly increased with an adequate return on investment for the operator. The freight advantage and potential product quality of New Mexican mica are important factors in the western mica markets. This investigation is essentially limited to muscovite mica; however, ground products made from sericite were also evaluated.