Abstract

Non explosive demolition agent (NEDA) is material that can produces static expansive stress during its chemical reaction. It can be an alternative method to changing of blasting role as rock cutter in hard rock mine. The important parameter to determine hole spacing are static expansive pressure by NEDA, rock properties, and borehole diameter. A laboratory experimental were conduct to assess the pressure gain until the maximum expansive pressure by using electrical strain gauge and dial gauge with using some sample with three differences diameter (Ø) with same height (10cm). Then, NEDA were use in larger sample as the physical model test (25cm × 45 cm × 45 cm), to assess the length of rock fracturing and monitor the crack growth with time considering. In case of laboratory experimental to determine hole spacing, some empirical equation and physical model result were employed to do some preliminary experimental. The differences of hole diameters and spacing and static expansive pressures were analyzed. Hence, the result of preliminary test were developed by statistical analysis using polynomial regression method. Then, by employed RS3 code as numerical modeling based on 3D finite element method the developed equation will be compared and validated. The developed statistical models were shown a good fitting with Finite Element analysis. Hence, the developed models can be used with confidence to determine hole spacing into rock fracturing.

1. Introduction

Mining industry in Indonesia was growth rapidly especially in quarry mine, like marble, granite, andesite, etc., but for excavation method, still use conventional method like diamond wire saw, and also blasting. Expansive mortar is an inorganic material that produces pressure that is expansive (expands) caused by hardening of the paste in the hydration process resulting in a tensile stress caused by shrinkage of chemical elements (odler, 2000). Expansive mortar is also one of the effective methods that can be used to breakage or cut the rock. Expansive mortar is widely used in the mining industry and civil construction.

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