In-situ investigation of drilling performance and bit wear on an electrical drill hammer

Abstract

Estimation of drillability is very important in rock drilling. Drilling performance and tool wear are two indispensable parameters for time and cost evaluation of an operation. In this article, by using an electrical drill hammer and two types of drill bits, in-situ drilling tests were conducted on three rock types to estimate the drilling performance and tool wear. Experimental results showed that the highest performance and the greatest bit wear occur in drilling sandstone, while the lowest values of penetration rate and wear are observed in amphibolite and basalt. Moreover, the penetration rate of drilling is related to rock mechanical properties. Regression analysis indicated that the correlation of performance with uniaxial compressive strength, Brazilian tensile strength and point load index, respectively, is significant and reliable. Regarding to the tool wear, equivalent quartz content showed a reasonable correlation with bit wear, compared to Cerchar abrasivity index and LCPC abrasivity coefficient.