Correlação entre características de rochas e rendimentos de corte com fio diamantado na lavra de rochas ornamentais.

Abstract

Traditionally the characterization of ornamental rocks is limited to the aspects related to the use of final products. That type of characterization is made for commercial purposes. However, there i t is possible to correlate those rock technological characteristics with quarry operations, especially regarding the utilization o f diamond wire sawing. The present research addresses the correlations among rock properties and performance of diamond wire sawing, during the extinction o f dimension stones. The study is based on a survey and analysis of operational data and technologic tests performed in a group o f silicate rocks, from quarries located in Paraiba and Rio Grande do Norte states. The operational parameter used in the correlations is the yield, that is, number of square meters of rock cut per linear meter of diamond wire, up to the complete wear o f the diamond wire. The technological characteristics of the analyzed rocks are the following: 1) Petrographic analysis, regarding the percentage of quartz and the weighted average o f the absolute hardness. 2) Uniaxial compressive strength, obtained indirectly using a point load test (PLT) equipment. 3) Flexure strength, based on standard procedures for dimension stones. 4) Amsler abrasion testing, also based on standard procedures for dimension stones. 5) Surface hardness, obtained using a Schmidt hammer device. The yield of diamond wire cutting is outlined based on the magnitude of the rock technological characteristics. For building a predictive model the rock properties that showed the best correlations were selected. The independent variables used were absolute hardness (Da) and Amsler abrasion index (Dam), that showed linear correlation coefficients equal to - 0,80 and 0,73, respectively. The dependent variable is the diamond wire yield (Rf). It has been observed that a model with multiple correlation showed a very good correlation coefficient, namely R = 0,9489. The model proposed i n the present research may be used for predicting the yield o f sawing operations using diamond wire. The proposed methodology, implemented by means o f statistical studies, constitutes a useful tool for avoiding unnecessary expenditures in the development of new quarries as well as for quarries in operation. The proposed approach is considered a practical and low cost technique.