For effective backfilling, a system with the 13 features covered under the cction: effective backfill systems, is required. Effective backfilling cannot be done with systems that are badly designed, outdated or over- extended. But in cases where the requirements for effective backfilling arc overlooked, the shortcomings of such systems may wrongly conk to be regarded as limitations to the capabilities of backfilling per se. Mining is currently done to depths of 3500 in, and is to go deeper since the gold-bearing reef extends down to 4000 in and 5000 in below surface. Effective backfilling systems will he required at such depths, ;and with suitable design this can he achieved. Mining the narrow tabular orehody of a typical South African gold mine is described at the start of this paper, then cycloned backfilling is discussed in general, and its effectiveness (most of the fill placed in South Africa is cycloned backfill or'deslimed tailings').