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1989 | Buch

Economic Evaluations in Exploration

verfasst von: Prof. Dr. Friedrich-Wilhelm Wellmer

Verlag: Springer Berlin Heidelberg

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Über dieses Buch

This textbook is a translation of the German textbook "Rechnen fUr Lagerstattenkundler und Rohstoffwirtschaftler, Teil 1" published by the Ellen Pilger Publishing Company. Those passages in the German edition which were especially written for the German readership were transform­ ed for English speaking readers. Compared with the German edition many chapters have been slightly amended. The main new additions in this English version are the chapter on linear optimization in Chapter 10.2 and Chapter 12 on the comparison of ore deposits. The textbook is intended for the economic geologist who deals with the evaluation of deposits at an early stage of development. Once an ex­ ploration project has reached the feasibility stage, the exact calculations of the deposit, the technical and economic assessment will be performed by a team of geologists, mining engineers, metallurgists, and economists. In the early stages of exploration, however, any evaluator of deposits has to be able to cover the whole spectrum himself. Since only order of magnitude parameters are available at this stage, the calculations can only yield order of magnitude results. Precise calculations would even be misleading, since the evaluation does not yet aim at accurate economic assessment but at making the right decision: should the investigation be abandoned or should it be continued at higher costs and with more detailed methods.

Inhaltsverzeichnis

Frontmatter
1. Conversions
Abstract
Exploration geologists working on an international level always have to convert measurements, weights and prices into different units. In this chapter the most important conversions and conversion factors mainly related to the “imperial” system of measures common in the Anglo-American field are listed. Although many countries, such as Canada or Australia, have adopted the metric system, time and again the exploration geologist will come across non-metric units in old texts.
Friedrich-Wilhelm Wellmer
2. Metal Prices
Abstract
One of the most important assumptions to be made in any economic evaluation is that of prices. Commodity prices can be found in special publications. For metals (see Chap. 1.2.7) the London-based, twice-weekly “Metal Bulletin” is the standard reference. The “Engineering and Mining Journal” publishes monthly price surveys for metallic and non-metallic commodities.
Friedrich-Wilhelm Wellmer
3. Calculation of Volume and Tonnage of Ore Deposit
Abstract
For the calculation of the volume and the tonnage of ore deposits there is a variety of available methods to choose from, each suited for a particular deposit. These methods fall into two categories: reserve calculation on the basis of cross-sections and on the basis of longitudinal planar sections or level plans respectively.
Friedrich-Wilhelm Wellmer
4. Weighting and Grade Determination
Abstract
Grade determinations will only be dealt with in this book if the calculations involve simple weighting with for example assay intervals in drill holes or with reserve block volumes.
Friedrich-Wilhelm Wellmer
5. Dealing with Data for Multi-Element Deposits
Abstract
Generally speaking, multi-element deposits contain more than one metal as a significant source of revenue. This applies to most non-ferrous metal deposits. Complex volcanogenic sulphide deposits often contain five components: Cu, Pb, Zn, Ag, and Au. In this case, each individual component has to be weighted separately as shown in Chapter 4.
Friedrich-Wilhelm Wellmer
6. Conversion of Geological Data into Mining Data for Ore Deposits
Abstract
The following chapters will deal with revenues and costs, i. e. with costs during the mining stage and revenues for the mine after a saleable product has been put on the market. The geological grades will seldom correspond with the grades of the mill head ore. As a rule the ore is diluted by inclusion of wall rock and losses occur during beneficiation. These factors have to be taken into account before revenues can be calculated.
Friedrich-Wilhelm Wellmer
7. Calculation of the Net Smelter Return (NSR) of a Mine
Abstract
As a rule, a mine produces concentrates. In rare cases it mines rich ores which can be shipped directly. In some cases price quotations for concentrates and ores are available, i. e. iron ore, tungsten, and antimony concentrates or “yellow cake”3, U3O8, the end product of uranium mines. These quotations are supplied by the price lists of the weekly “Metal Bulletin” or the “Engineering and Mining Journal”. Generally these prices are quoted in “units”, with 1 unit (1 u) being 1% of the metal in the concentrate (see Chap. 1.1.4.6). From this the net smelter return of the mine can easily be derived.
Friedrich-Wilhelm Wellmer
8. Production Lifetime
Abstract
The preceding chapters demonstrated how net returns per ton of ore can be calculated. They are, of course, only dependent on ore grades and not on the amount of ore mined. When considering the production costs, the output per unit of time must also be taken into account. The greater the output per day or per year, the lower are the costs per ton of ore. This effect is called “economics of scale”.
Friedrich-Wilhelm Wellmer
9. Calculation of Cost Data
Abstract
After having determined the capacity of the potential mine (Chap. 8), cost data will have to be calculated.
Friedrich-Wilhelm Wellmer
10. Additional Economic Planning Methods
Abstract
Before going into economic calculations two economic planning methods shall be considered which can influence the economics of an ore deposit:
  • — determination of a cut-off grade;
  • — linear optimisation when there are several alternatives.
Friedrich-Wilhelm Wellmer
11. Economic Evaluations
Abstract
Now that we know how to calculate the revenues for a potential mine from the grades of a deposit to be evaluated (Chap. 7), how to determine the lifetime of a mine (Chap. 8), and how to derive capital and operating costs from the capacity (Chap. 9), we have all the data required to carry out economic calculations.
Friedrich-Wilhelm Wellmer
12. Comparison of Deposits
Abstract
Both in preliminary evaluations and final feasibility studies the deposit under investigation is frequently compared to other deposits which are either in production or still in the preproduction stage. The best comparison is an eco nomic one. In the preliminary stage, however, when only order of magnitude para meters are available, other “semi-economic” methods of comparison are also used.
Friedrich-Wilhelm Wellmer
13. Calculating Growth Rates
Abstract
A strategic question is often raised in connection with the evaluation of a deposit: What will the future demand for the metal (or metals) in the deposit under consideration be like? Does an analysis of the planned mining projects reveal shortfalls in satisfying demand?
Friedrich-Wilhelm Wellmer
14. Equity Calculations
Abstract
Equity calculations will be considered under two aspects:
  • — equity calculations with several partners;
  • — calculations of possible foreign equity in countries where foreign investment is limited.
Friedrich-Wilhelm Wellmer
Backmatter
Metadaten
Titel
Economic Evaluations in Exploration
verfasst von
Prof. Dr. Friedrich-Wilhelm Wellmer
Copyright-Jahr
1989
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-662-02578-9
Print ISBN
978-3-662-02580-2
DOI
https://doi.org/10.1007/978-3-662-02578-9