The Availability of Indium: The Present, Medium Term, and Long Term
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- Appendix D: Methodology Used To Derive the Short- and Medium-Term Supply Curves
- The Short Term
- Table 26. Mount Pleasant Production and Product Revenue Summary for Production Cases “A” Through “C” Parameter Units
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications Appendix D: Methodology Used To Derive the Short- and Medium-Term Supply Curves Primary indium production is largely the result of byproduct production from sphalerite (zinc) ores. As such, it is not significant to most indium-producing mining companies, and the value chain from mining to refined metal often involves several companies with few companies spanning the entire value chain. Furthermore, with total global primary production valued at approximately $493million, 41 indium recovery is likely not of key economic importance for many smelters or special metal refineries. As a result, data surrounding the explicit incremental costs to recover indium are not publically available and, because costs are intermingled between main product, coproduct, and byproduct metals, miners and smelters probably do not explicitly track the costs of indium internally. As is often the case with mineral properties, technical reports filed by midsized and junior mining companies with the securities exchanges as part of their disclosure requirements contain the best and most detailed information available. 42 This information can then be used together with various resource characteristics, recovery efficiencies, costs of capital, etc. to generate a representative view of costs and production levels for various deposits. We adopt this approach when examining what a supply curve for indium might currently look like and how this might change going forward. We use a Monte Carlo simulation to generate short- and medium-term supplies. As will subsequently be discussed in greater detail, we use data from the following sources to build the supply curves: • A recent preliminary economic assessment of the Mount Pleasant indium-zinc-tin deposit in Canada (Thibault et al. 2010) • A catalogue of known indium-bearing deposits (Schwarz-Schampera and Herzig 2002) • Historical (long run) commodity prices for tin and zinc • Growth of main product zinc production and therefore extrapolated byproduct indium production • Estimates of medium-term potential recovery efficiencies at new facilities (Thibault et al. 2010). The steps taken to generate the results differ slightly between generating the short- and medium- term supply curves. In the short term, the indium need only cover its share of direct operating costs; in the medium to long term, the indium needs to cover operating and capital costs and generate a fair return to capital. We now look at each of these approaches in detail.
Focusing first on the short run, the operating cost estimate for the Mount Pleasant deposit is examined in detail (Thibault et al. 2010). The preliminary assessment for Mount Pleasant
41 Assuming 822 tpa of indium metal × 1000 kg/tonne × $600/kg indium metal. 42 Large mining companies are often not required to disclose detailed technical information about development projects or ongoing operations, because the performance of a single operation is not essential to the overall value of the company.
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications contains three production cases labeled “A,” “B,” and “C,” all of which assume that same mine and plant head feed capacity but vary the degree to which the zinc, tin, and indium are refined. In case “A” the design accommodates the recovery of a tin concentrate as well as a combined indium and zinc concentrate. These concentrates are then shipped to third-party smelters for further processing. Case “B” includes the concentrator plant from case “A” to recover a tin concentrate that is shipped to third-party smelters; however, the treatment plant is expanded and includes a hydrometallurgical plant for production of indium sponge of 95% purity and zinc metal. Indium sponge is then pressed into briquettes and shipped to a third-party refinery for upgrading to 4N8 purity. The zinc metal is sold directly to the market. Case “C” includes the concentrator/hydrometallurgical plant of Case “B” indium sponge and zinc metal in addition to a pyrometallurgical plant for production of tin chloride instead of tin concentrate. Various design parameters for the three cases and their respective final products are summarized in Table 26.
Annual production rate DMT a /yr 3231 2142 8,658
4056 40.5
Product grade wt%
46.0 wt%, Tin
99%, Tin Chloride 50% Zinc, 0.49% Indium 99.50% 95% Indium Market price C$ b
$16.25/kg Tin
$15.23/k g 99%
Tin Chloride $2.70/kg Zinc, $639.67/kg Indium $2.70/kg Zinc $639.67/kg Indium (4N) Market price adjustment C$/kg
n/a n/a
n/a n/a
81.38% c
Total treatment charges
C$/DMT $783.37 $0
$390.60 $0
$66,000 d
Total unit deductions wt%
3.70% Tin 0%
8.00% (Zinc) 0%
0% Annual revenue C$mn/yr $20 $33
$11 $11
$17 Revenue relative to 100% market % 81.50% 100% 54.3% (Zinc) 15% (Indium) 100%
71.10% Mill characteristics
850 tpd design capacity, 90% availability, 279,226 tpa Applicable to case A
Y N Y N N Applicable to case B
Y
N Y Y Applicable to case C
N Y N Y Y a DMT = dry metric tonnes; "conc." = concentrate. b C$ refers to Canadian dollars. The conversion used by Thibault et al. (2010) at the time of drafting their report was C$1.10/US$. c Market price adjustment factor accounts for loss of indium in refining process to 4N8 grade and a price discount for indium sponge relative to the price for 4N indium. d Indium sponge treatment charges are per tonne of 4N* indium metal recovered after refining losses. Source: based on Thibault et al. 2010
To assess the cost of producing indium, we concern ourselves with cases “A” and “B” only, because the upgrading of tin concentrate to tin chloride is not of interest. In the case of the Mount Pleasant property, 40.5 tpa of indium may be produced as a coproduct along with zinc Yüklə 1,06 Mb. Dostları ilə paylaş:
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