Revegetation of mine wastes at Mt. Isa, Queensland. 2. Amendment of nutrient status and physical properties of tailings for plant growth

Abstract

Pot and field trials were undertaken to examine methods to overcome chemical and physical limitations of metal mine tailings to plant growth. Marked responses to phosphorus and nitrogen were demonstrated in pot trials. Reduction of soluble salt levels by leaching markedly improved plant growth. Fly ash from coal fired power stations was shown to be an extremely efficient amendment for tailings bringing about a reduction in bulk density, surface crust strength, and increasing infiltration rate which improved the leaching of soluble salts. Toxicity problems were not apparent, and plant growth improved with increasing proportions of fly ash in mixtures with tailings. The marked effect of fly ash additions was demonstrated in field trials. No plant growth was evident in plots without fly ash, whereas fly ash treated plots maintained quite high levels of plant growth over a number of years.