Exploitation by the cemented backfilling method of the talc orebody at the Fontane Mine, Italy: A research on filling mix optimisation

The Fontane Mine is long since exploited by a descending slicing method, where voids are backfilled with a lean concrete. The paper, after a synthetic overview of the current mining practice, analyses in detail the properties of the filling mixes and of the resulting cured mass, for the different backfill placing methods employed. In particular: the influence of the aggregates used and of the cement-water-aggregate ratios; the requirements of the mix dictated by the placing method (either sling belt, or pumping); the strength and the deformability of the cured mass of fill. In the concluding remarks, advises for the obtainment of a satisfactory fill from the available material (mainly mine waste) are given, deduced from the comparison of the results of laboratory tests to the fill properties obtained from measurements on samples of the actual fill mass and from in situ tests.