Incorporating the monolithic nature of paste backfill into self heating assessments

Tailings have exhibited self heating behaviour due to exothermic sulphide oxidation. Self-heating in paste backfill has caused dangerous temperatures and SO₂ concentrations. Self-heating potential is commonly evaluated using a laboratory test in which heated air is forced through crushed material. However, due to the monolithic nature of backfill, including a very low permeability to oxygen and moisture, laboratory tests using a pulverized sample may be conservative and conducting tests with monolithic samples may be more representative. Field trials were conducted at Voisey’s Bay Mine, Canada.