Zinc Stocks!, page-29

That's not correct @aussieman.

The rate per tonne.km is generally not dependent on the SG of the material unless the material is so light that the truck can't be filled. If a 50t capacity truck hauls 50 tonnes 4 kilometres then the contractor will be paid for 200 t.km irrespective of SG.

A weightometer just allows more accurate tonnage estimates and thus better info for contract claims and mine reconciliation as well as monitoring truck loading to ensure that trucks are being loaded consistently at their rated capacity.