Paper Title
An Economic Evaluation of Granite Quarry for Aggregate of the Silasiam Mine Co., Ltd at Kanchanaburi Province, Thailand

Abstract
Silasiam mine is a large granite quarry for aggregate used for high building construction and road infrastructure. 2.4 Mtons of granite rock is produced as aggregate annually with a reserve of 48.4 Mtons. The objective of this study is to maximize the underlying value of the mineral resource by improving project concepts, optimizing the project development plan while minimizing risks in order to make a firm decision for investment. The Discounted Cash Flow (DCF) model was adopted to evaluate project finance under the NPV, MIRR and payback period criteria. A given -30% to +30% of CAPEX, OPEX, and Price applied as independent variable values impacted a particular dependent variable to be a sensitivity analysis. Based on our study, the project time frame is 20 years which spends 19 years for operation and one year for preparation and development. It requires US$ 20.3 million of capital cost and US$ 2.8 million of operating costs annually. The financial analysis indicated that the NPV8% is US$ 77.06 million, MIRR is 17.29% and a payback period of almost two-years. The sensitivity analysis shows that the most sensitive value is the aggregate price. However, the project can withstand up to 30% drop in aggregate price or over 30% increase in capital and operating cost. Keyword - Granite quarry, Aggregate, Discounted Cash Flow, Net Present Value, Modified Internal Rate of Return, Sensitivity Analysis.