Diagnóstico e sugestões para a melhoria da lavra em pegmatitos na província da Borborema.

Abstract

Mining of Borborema Province pegmatite is an economic activity that ensures the support of many small miners, however, the recovery of the resources takes places in a precarious way, disorganized, informal and predatory, which is developed largely by the so called garimpeiros. The garimpeiros have little technical knowledge, what compromises the recovery of the deposits an also the surrounding environment, as well as jeopardizes the safety of the workers involved in the extractive process. The present research addresses the following topics: the drilling methods, blasting, loading of the muck pile haulage of the pegmatite rocks. It is also analyzed the stability of the excavations, the safety conditions, ventilation, and the resulting environmental impacts, the main extractive activities, produced minerals, production processes, commercialization, applications and the restrictive aspects of the mining process. Two mining methods are proposed, a surface mine method and na underground method, for the pegmatite body known as Alto do Daniel, located in Jardim do Serido. County, Rio Grande do Norte State, where the implementation of those methods will ensure the rational recovery of the mineral resources, thereby allowing for the sustainable development, that will result in competitive advantages for the small informal mineral producers of the region, besides the minimization of the environmental impacts resulting from the extractive activities. The proposed surface mining was planned using 3 simultaneous benches 3 meters high, allowing for the total recovery of the body, and permitting the longitudinal haulage of the ore along the pegmatite. The underground mining method takes places in advances from the extremes to the center of the body, developed by two parallel drifts, each 3 meters high by 2.5 meters wide, and a crown pillar 5,5 to 6,5 thick. Localized rock bolts are proposed for stability of the drifts.