Copper smelters: separate treatment fees and metal result
Copper concentrate purchasing combines a physical material quantity with contractual pricing units. A treatment charge quoted per dry tonne and a refining charge quoted per payable pound cannot be added until both are converted into money on the correct bases. The research task is to reproduce the purchase settlement and identify what remains before other costs and by-products.
This worksheet concerns commercial quantities and evidence. It does not prescribe a smelting process, predict metallurgical performance or assign universal contract terms to the industry. Keep contained copper, payable copper and recovered saleable copper in separate columns. Their differences may affect a commercial result, but they represent different measurement or contractual objects.
Locate the pricing mechanism
Aurubis’s Annual Report 2024/25 includes a Pricing along the value chain heading on PDF page 121. Its schematic and accompanying paragraphs describe treatment and refining charges as negotiated deductions in raw-material purchasing and distinguish the copper price, premium and product surcharge on the sales side. The earnings-driver table on PDF page 120 separately lists TC/RC, metal result and sulfuric-acid revenue.
Those sections support separating the mechanisms. They do not supply the invented contract below, a universal payable percentage or a promised profit margin. Use the PDF page number explicitly when locating the passages; a browser’s page counter and a printed report page can differ. Do not substitute a commodity-market forecast elsewhere in the report for the contract’s actual settlement terms.
Request a settlement statement, quantity certificate, assay basis, price period and charge schedule. If the public report supplies only segment earnings drivers, the worksheet can explain sensitivities but cannot reconstruct an actual supplier invoice. Record that difference in evidence strength before introducing any estimated quantities.
Rebuild one fictional concentrate purchase
Assume one thousand dry metric tonnes of concentrate with a 25% copper assay. Contained copper is 1,000 × 25% = 250 metric tonnes. Assume a fictional agreement pays for 98% of contained copper, so payable copper is 245 tonnes. This percentage is an explicit teaching assumption, not a claim about Aurubis’s contracts.
The assumed copper price is $9,000 per metric tonne. Payable metal value before deductions is 245 × $9,000 = $2,205,000. Treatment charge is $80 per dry tonne, giving $80,000. Refining charge is $0.08 per payable pound. Use 2,204.62262185 pounds per metric tonne, keeping enough precision before final rounding.
Payable pounds are 245 × 2,204.62262185, approximately 540,132.54 pounds. Refining charge is approximately $43,210.60. Thus the simplified purchase payment is $2,205,000 − $80,000 − $43,210.60 = $2,081,789.40. It excludes freight, penalties, provisional payments, taxes, other metals and every contract term not explicitly included.
| Settlement step | Basis | Amount |
|---|---|---|
| Contained copper | 1,000 dry tonnes × 25% | 250 tonnes |
| Payable copper | 250 × 98% | 245 tonnes |
| Payable metal value | 245 × $9,000 | $2,205,000 |
| Treatment charge | 1,000 dry tonnes × $80 | $80,000 |
| Refining charge | 245 tonnes converted to pounds × $0.08 | $43,210.60 |
| Simplified purchase payment | Value less both charges | $2,081,789.40 |
Every charge has its own denominator. Applying the refining charge to one thousand tonnes of concentrate rather than payable copper pounds would price the wrong object. Applying treatment charges per contained copper tonne would make the same mistake in a different direction.
Isolate the commercial metal difference
Assume, solely for this commercial scenario, 247.5 tonnes of copper become saleable and receive the same $9,000 price. Sales metal value is $2,227,500. This recovered quantity is an assumed outcome, not an operating recipe or an assertion that a real shipment will produce it.
Sales metal value less the simplified purchase payment equals $145,710.60. Reconcile it in two parts: TC plus RC totals $123,210.60, and the difference between saleable and payable copper is 2.5 tonnes, valued at $22,500. The two parts sum to the same $145,710.60.
If the defined processing-cost basket is $140,000, the remaining contribution is $5,710.60 before omitted items. It is not net income, free cash flow or the report’s entire metal result. Keep depreciation, financing, hedges, freight, by-product sales and other omitted lines visible. A neat settlement bridge becomes misleading if its endpoint is relabelled as a complete operating margin.
Test price and payable boundaries separately
Raise the assumed copper price to $10,000 while keeping all physical quantities and charges unchanged. The 245 payable tonnes also become more expensive to purchase. Only the 2.5-tonne assumed saleable-payable difference gains an extra $2,500 in this simplified matched-price bridge. Multiplying the entire saleable quantity by the price increase and calling that incremental profit ignores the input liability.
Real purchase and sales quotation periods may differ, and hedges may change the accounting result. Therefore this sensitivity illustrates matched commercial exposure, not an actual unhedged position. If the dates or price bases are missing, do not select whichever quotation creates the largest margin. Show separate pricing assumptions until the documents establish comparability.
A different boundary concerns moisture. One thousand dry tonnes at 10% moisture on a wet-weight basis corresponds to approximately 1,111.11 wet tonnes: dry quantity equals wet quantity × 90%. Applying the $80 dry-tonne charge to the wet quantity would overstate the charge by approximately $8,888.89. Confirm how moisture is defined before converting; a percentage with another basis needs another calculation.
Payability is also not recovery. A 98% contractual payment factor does not prove 98% of copper physically emerges from processing. Compare assay, payable rules and actual saleable output separately. An apparent metal gain can disappear when the assay is revised or the output measurement belongs to a different shipment cohort.
Use the settlement verification sheet
| Input | Primary evidence | Check |
|---|---|---|
| Material quantity | Weighing and moisture statement | Wet versus dry tonnes, shipment identity |
| Assay | Agreed assay and revision | Contained metal, units and settlement status |
| Payable basis | Contract schedule | Percentage, deductions and applicable metal |
| TC/RC | Charge schedule | Currency and each physical denominator |
| Pricing | Quotation period and settlement | Purchase versus sales price dates |
| Output and costs | Matched production and cost records | No purchase/output cohort mismatch |
When public commentary and a settlement differ, first reconcile dry versus wet basis, provisional versus final assay, payable versus contained metal and the covered quotation period. Do not average conflicting numbers. A remaining gap belongs in a named unresolved line, rather than being automatically classified as processing efficiency or fraud.
Where penalties or by-product terms are unavailable, present the copper-only bridge and an explicit missing-items list. Do not set every omitted item to zero and label the result actual profit. Uncertainty about an invoice term is different from uncertainty about future copper prices and should have a separate scenario cell.
Update when final assays, settlement prices, charge schedules, product premiums, output allocation or cost boundaries change. Preserve provisional versions and the reason each number changed. The conclusion should state which settlement elements are reproduced, which are assumptions, and why a copper-price move alone does not establish a proportionate earnings improvement.
Preserve the provisional-to-final settlement bridge
A shipment may first be recorded using provisional quantities, assays or prices. Keep that version and reconcile the final settlement by quantity change, assay change, price fixation and fee adjustment. The components should reproduce the final purchase amount without assigning every difference to TC/RC.
Cash paid can follow a different path from the final material cost. An advance payment is not a new charge merely because it appears on a bank statement. Maintain separate columns for accrued purchase value, cash paid and outstanding settlement. Without that distinction, a timing improvement can be misread as a better processing spread.
Finally, preserve product boundaries when matching output. Saleable copper from several feed streams cannot automatically be attributed to the one concentrate shipment in the example. If shipment-level recovery is unavailable, keep it as an assumed allocation and test the result under a range. A segment’s reported metal result may include other metals and inventory effects, so failure of this narrow copper bridge to equal that segment number is not itself a contradiction. Request the definition rather than forcing the residual into an invented recovery gain.
FAQ
Is payable copper the same as recovered copper?
No. One is a contractual payment basis; the other is a physical output measurement or explicit scenario assumption.
Do higher copper prices automatically improve this contribution?
No. The purchase price also changes, and actual exposure depends on quantities, price periods and hedging.