Permeability of Hydraulic Fills and Barricade Bricks

Abstract

Permeability is one of the most important parameters in the design of hydraulic backfilling of mine stopes. A simple and reproducible method was developed for preparing reconstituted hydraulic fill sample in the laboratory, that is representative of the hydraulic fill in the mine stope, replicating the slurry sedimentation process taking place in the mine. Constant head and falling head permeability tests were carried out on the samples, giving consistent results. A brick permeameter was developed to study the flow characteristics of the porous barricade bricks under one-dimensional flow, simulating the flow conditions in the mine. Three different methods were used to determine the permeability of the brick and the results showed very good agreement. This is the first rational attempt to measure the permeability of the porous barricade bricks that are used to close the horizontal access drives in the mines, thus retaining the hydraulic fill. The measurements show that the permeability of the barricade brick is about two to three orders of magnitude greater than that of the hydraulic fill.

Underground Mine Backfilling in Australia Using Paste Fills and Hydraulic Fills

“…To allow the excess water to drain, the barricades are constructed using specially made porous barricade bricks. Sivakugan et al [6] measured the permeability of these special bricks and found them to be 100-1500 times larger than those of the hydraulic fills. Therefore, the barricade can be assumed to be free draining in any numerical modelling work on the drainage through hydraulic fills.…”

Role of inertia in falling head permeability test

“…The obtained results may explain Table I. systematic difference between values of permeability determined through constant and falling head method for high-permeability materials which can be found e.g. in [3] while it is evident that disregarding micro-inertial forces leads to overestimation of permeability in both types of tests. …”

“…The problem seems to be important if we notice significant difference between values of permeability determined from constant and falling head test for high-permeability materials, as reported e.g. in [3].…”

Horizontal pressure on barricades for backfilled stopes. Part I: Fully drained conditions

“…A critical engineering challenge is the evaluation of the stress state within the backfill and the associated pressures exerted on the stope walls and barricade (or bulkhead) constructed at the base of the stope to retain the fill. The latter aspect is particularly important because a number of barricade failures have been reported over the years (e.g., Soderberg and Busch 1985;Grice 1998Grice , 2001Kuganathan 2001Kuganathan , 2002Sivakugan et al 2006aSivakugan et al , 2006bHelinski and Grice 2007;Yumlu and Guresci 2007). Barricade failures in underground mines may lead to serious consequences, including flooding of the drifts, damage to equipment, and in extreme cases personnel injury or fatality.…”