How it is calculated
- Price per dry tonne = price per dmtu × grade (%)
- Dry tonnes = wet tonnes × (1 − moisture ÷ 100)
- Contained metal (tonnes) = dry tonnes × grade ÷ 100
- Units (mtu) = dry tonnes × grade
- Shipment value = dry tonnes × (price per dry tonne − deductions per dry tonne)
Worked example
A 5,000 tonne parcel of ore assaying 44% Mn with 3% moisture, priced at $4.50 per dmtu with no deductions. Price per dry tonne = 4.50 × 44 = $198.00. Dry tonnes = 5,000 × 0.97 = 4,850. Contained manganese = 4,850 × 0.44 = 2,134 tonnes, or 213,400 mtu. Shipment value = 4,850 × $198.00 = $960,300. The same parcel is $192.06 per wet tonne.
Frequently asked questions
How do I convert dmtu to a price per tonne?
Multiply the price per dmtu by the grade in percent. $4.50 per dmtu on 44% ore is 4.50 × 44 = $198 per dry tonne.
What is the difference between wet and dry tonnes?
Wet tonnes include the moisture in the ore. Dry tonnes exclude it, and dmtu prices are paid on dry tonnes, so 5,000 wet tonnes at 3% moisture is 4,850 dry tonnes.
How are penalties applied?
Deductions for elements such as phosphorus, silica and alumina are subtracted from the price per dry tonne before the total is calculated. Enter them in the deductions field. The penalty calculator on this site works them out from the contract terms.
How many mtu are in a tonne of ore?
The same number as its grade in percent. A tonne of 44% ore holds 44 mtu.