Mineral specification we buy
Before we talk price, we talk assay. Most of the ore offers we receive are not turned down on price — they are turned down on a lab report. This page sets out exactly what the material has to meet before we can process an offer, so you know whether your mineral fits before moving a single tonne.
Maximums accepted
These are the limits accepted by the buyers we source for. They apply to every mineral we purchase.
| Element | Symbol | Maximum accepted |
|---|---|---|
| Arsenic | As | < 0.5% |
| Mercury | Hg | < 0.005% |
| Cadmium | Cd | < 0.005% |
| Sulphur | S | < 9% |
| Fluorine | F | < 0.10% |
| Moisture | H2O | < 5% |
| Particle size | — | 20-40 mm |
Figures are percentages on a dry basis, backed by laboratory analysis. Offers exceeding any of these limits cannot be processed by our buyers.
Why these limits exist
This is not paperwork. Every one of these numbers maps to a real cost somewhere in the chain.
Smelter
Arsenic, mercury and cadmium are penalised on payment, or make the smelter reject the cargo outright. These three break more deals than anything else.
Process
Fluorine attacks the furnace refractories. Sulphur drives the entire gas-treatment side of the plant. An out-of-range concentrate forces the buyer to blend it or turn it down.
Freight
Above 5% moisture you are paying freight on water, and with certain concentrates the risk during the voyage rises. Particle size affects port handling and furnace feed.
Customs
Heavy metals are regulated at both origin and destination. An out-of-spec shipment can be held at either end.
How a deal works with us
The order matters, and it is always the same:
- Your proposal. The producer or trading company sends us its offer with these figures. No proposal, no site visit and no negotiation.
- Feasibility assessment. If the material complies, we reply with our counter-proposal: price with its discount table and terms.
- Contract. Once both sides agree, a sale and purchase contract is drawn up. We travel to source — mine, warehouse or stockyard — only when the case calls for it.
- Follow-up to destination. Departure from the warehouse, vessel loading, voyage and arrival, with documentary control across the supply chain.
What if my material is out of range
We will tell you, and the sooner the better. Out-of-spec material is not always a final no: depending on the element and the deviation there may be options — blending with another lot, pre-treatment, or a different buyer with different tolerances. What we will not do is process an offer we know the smelter will reject.
Minerals we buy
This specification applies to all of them:
- Copper concentrate — 20-30% Cu
- Zinc concentrate — 50-55% Zn
- Lead concentrate — 60-75% Pb
We also buy antimony, nickel, tin, gold and molybdenum. Minimum volume from 100 MT.
Send your proposal
Our supplier portal validates every figure as you type it and flags anything out of range before you submit. It is the fastest route: if your material is in spec, the conversation starts the same day.
Register my offer on the supplier portal →
You can also write to info@group-mtw.com.