عنوان مقاله
بررسی تاثیر هزینه های عملیاتی عدم قطعیت ها در ارزیابی پروژه معدن
فهرست مطالب
مقدمه
درخت دوجمله ای
روش پژوهش
تجزیه و تحلیل حساسیت
نتیجه گیری
بخشی از مقاله
سناریو 2: قیمت فلز نامشخص و برخی از وضعیت هزینه های عملیاتی
در این سناریو، قیمت فلز نامشخص در نظر گرفته شده است اما مانند سناریوی قبلی، هزینه های عملیاتی مشخص فرض شده است. درخت دو جمله ای، که با استفاده از داده های قدیمی ساخته شده است برای برآورد تغییرات آینده قیمت فلزات استفاده شده است. بنابراین، یک درخت جدیدFCF دو جمله ای با استفاده از درخت دوجمله ای قیمت فلز ساخته شده است ، که سالانه هزینه های عملیاتی و معادله (4) را برآورد می کند.
کلمات کلیدی:
Determination of the effect of operating cost uncertainty on mining project evaluation Hesam Dehghani 1 , Majid Ataee-pour n Faculty of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran article info Article history: Received 21 October 2011 Received in revised form 28 November 2011 Accepted 29 November 2011 Available online 4 January 2012 JEL classification:: Q39 Keywords: Economic uncertainty Metal price Operating costs Net present value Binomial tree technique abstract Mining projects are complex businesses that demand constant risk assessment. This is because several kinds of uncertainties influence the value of a mine project, typically. These uncertainties may be classified as exploration uncertainties, economic uncertainties and engineering uncertainties. The evaluation of a mine project under these uncertainties is a complicated job, which may lead to making a wrong decision by managers and stockholders. Therefore, at first, the engineers must recognize the mining uncertainties before carrying out the project evaluation. The economic uncertainties are the most important factors, which may affect the project evaluation. Among the mentioned uncertainties, the operating cost uncertainty is an important and effective factor, which is ignored to a certain extent. This research uses the binomial tree technique to compute the net present value of the Cayeli copper mine under three scenarios: (1) assuming certainty for both price and operating costs, (2) assuming uncertainty for metal price and certainty for operating costs and (3) assuming uncertainty for both price and operating costs. It is concluded that the mine evaluation suggests greater net present value when uncertainty is considered for both price and operating costs. & 2011 Elsevier Ltd. All rights reserved. Introduction Mining projects are complex businesses that demand a constant assessment of risk. This is because the value of a mine project is influenced by many underlying economic and physical uncertainties, such as metal prices, ore grades, costs, schedules and environmental issues. Therefore, evaluating and estimating a mine project without mentioning the risk for future losses (or opportunities) will lead to invalid results. Consequently, managers and stockholders of a mine company make an indiscreet decision based on invalid information. The main sources of uncertainty arising at the beginning of a mine project can be categorized into three groups: exploration uncertainties, engineering uncertainties and economic uncertainties. Exploration uncertainties will occur in the duration of resource evaluation stages such as geologic uncertainty, data collection, interpretation, modeling, deposit classification, reporting and so forth. Many researchers such as Dowd (1997), Dimitrakopoulos et al., (2002), Dimitrakopoulos et al. (2007); Godoy and Dimitrakopoulos (2004), Leite and Dimitrakopoulos (2007), Rendu (2007) and Dimitrakopoulos et al., (2009) studied these types of uncertainties. Engineering uncertainties include bench heights determination, planned grade control, minimum stoping widths, choice of stoping method, dilution factors, geotechnical and hydrological parameters, mining recovery factors and metallurgical recovery. This type of uncertainty will affect the ultimate pit (stope) limit and scheduling period. Economic uncertainty is another important source of uncertainty, which has a critical impact on mine project evaluation. From the economic point of view, future metal prices and operating costs are the most important factors of uncertainty. The metal price is the real cash-settlement that represents the equilibrium or non-equilibrium of the metal market. Since this market is based on demand, supply and other factors such as speculation, news events and dividend payouts (Fanning and Parekh, 2004; Case and Fair, 1989; Taylor et al., 2000), uncertainty on future metal prices arises because of two main factors (MacAvoy, 1988): – The lack of exact knowledge of those factors leading to the increase/decrease in metal supply and demand. – The practices that producers or consumers perform in the face of powerful speculative and political motives.
