Mineral deposits in Rio Arriba County, New Mexico
— Virginia T. McLemore and Gretchen Hoffman

More than $40 million worth of mineral production has come from 14 types of deposits in 19 mining districts in Rio Arriba County. Three of these districts (Nacimiento, Jemez pumice, No Agua) are considered significant deposits for copper, silver, and pumice, although known large deposits are in adjacent counties (Taos, Sandoval). However, the presence of these significant deposits and the potential for discovery of additional metals resources in the Bromide No. 2 and Hopewell districts in Rio Arriba County should encourage exploration in the county. Despite the presence of remaining resources of feldspar, mica, niobium, rare-earth elements, and beryllium, it is unlikely that the pegmatites in the Petaca and Ojo Caliente districts will ever produce again because of small size and grade. Only the Menefee Formation coal at shallow depths has limited economic significance in the Moreno coal field, where preliminary estimates indicate demonstrated resources at a depth of 61 m are 8 million short tons. Currently only aggregate pits (sand and gravel, scoria, pumice) are active and production of aggregate (sand and gravel, pumice, and scoria) is likely to continue in the future.