Problems encountered with the Old Ben system prompted the design of Wongawilli system of Pillar extraction, and the following parameters were set: 1. Provision of a single working place 2. Extraction of coal in stress relieved areas 3. Utilisation of the coal in stress as a support 4. Maximise extraction of […]

When the statutory limitations on pillar extraction by mechanical means were lifted in NSW, a number of problems became evident due to the time which had elapsed from the development of the original workings. Many pillars had partially crushed due to the time they had stood unworked or due to […]