Breakdown: non-ferrous concentrates

Metal concentrates (e.g. copper, zinc, lead) are mined rock upgraded to a powder containing a percentage of metal — copper concentrate is typically ~20–30% copper. You don't get paid for the rock; you get paid for the recoverable metal inside it, priced off the exchange, minus the cost of smelting it.

Assay

Lab analysis establishing the metal grade and impurities in the concentrate.

Payable metal

The percentage of contained metal the buyer actually pays for (e.g. ~96.5% of copper, after a fixed deduction).

TC/RC

Treatment Charge / Refining Charge — what the smelter deducts to turn concentrate into refined metal.

Quotational period (QP)

The averaging window of LME prices used to set the final value.

Penalties

Deductions for impurities (arsenic, etc.) above agreed thresholds.