Continuous research in this area has developed a water-free backfill paste using total tailings without dewatering and size classification. With this technology the limitations and and technical restrictions of the conventional pastefill are eliminated. It will eliminate bleed water and provide effective early support to the ground. The paste is made by adding a special binder, HiFa Bond, to the tailings during the course of backfill delivery. The binder has superior properties over Portland cement. Experiments were conducted on paste design, paste optimization to increase its strength and reduce cost, working time control and column flow tests in the following conditions: paste pulp density 65% to 80%, binder content 2% to 10%, with a desired compressive strength 0.5 to 1.5 MPa at curing time 1 day to 28 days. Reinforcement by adding aggregates and fly ashes were also be studied. The results have been very satisfactory and prompted potential industrial applications.
This research will benefit both the mining industry and the general public. It is expected to overcome the problems associated with backfill and will:eliminate the water decant problem
be suitable to all types of tailings regardless of the particle size,
fine content and water content
do away with the expensive dewatering process in preparing tailings
reduce or eliminate pipeline plugging.
Overall, it will simplify the backfill process, reduce the operation costs and make paste fill possible to all underground mines. Most importantly, it will provide a means of environment protection by removing the pollution source. The added benefit is the savings on producing backfill materials since tailings are essentially wastes on mine sites.
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