Effects of Blast Design to the Environment in Limestone Quarry

Abstract

The demand for construction materials produced by quarry rises in tandem with urbanization. The enormous number of complaints, however, has put the quarry owner under constant pressure to ensure safe blasting operations and minimal blasting effect on the environment. Due to the fact that limestone naturally dissolves in water and creates numerous weak spots in rock masses, it has always been thought that limestone quarry operations are more risky than common granite quarry operations. The goal of the study was to identify the rock mass properties of limestone and how they related to the consequences of blasting operations. For a systematic study, the quarry face was divided into four (4) Sections i.e., Section A, Section B, Section C, and Section D. The preliminary study was involved site investigation for quarry face evaluation and data collection as well as results from blast monitoring program for two months in a row was also recorded. The analysis was started with calculation of Blastability Index (BI) of the study area based on rock mass properties data and Blastability Quality System (BQS). The new predicted site constant (rock mass properties), κ and β were calculated based on two globally recognized empirical equations i.e., USBM and Langefors-Kihlstrom and the results was employed as indicator for future blasting operations. The SPSS Regression Model analysis graphs shown USBM predictor was inversely proportional to the PPV, while, the Langefors-Kihlstrom predictor graph was proportional to the PPV. The calculated K and β values for USBM predictor was 40 and 1.0 respectively. Based on the analysis, the rock mass properties at this limestone quarry have high influence to blasting effects and the effect can be aggravated at certain study sections. From all sections, Section A was deemed the most sensitive area or has the highest risk of generating excessive environmental effect with the lowest BI value (higher rock strength) at 49.18%, located closest to sensitive public buildings and recorded the most joint sets. It is can be concluded that the blasting activities in this quarry although at maximum charge per delay (Wmax) was being carried out safely with very minimal effects to the surrounding areas and in accordance to the limits set by the relevant authorities i.e., JMG and DOE Malaysia.