Reilly, W.I. 1954 Convergence in Paparoa State Coal Mine: September 1953-April 1954. : . Report / Geophysics Division 18 ?
Abstract: Convergence recorders have been used to study the unusually large rate of convergence which occurs in the Aerial Section of the Paparoa State Mine. The current workings in this Mine traverse previous workings which have completely closed up. The observations show that the rate of convergence in a new drive depends on the amount of coal that has been removed from the same vicinity during the previous work. The convergence is relatively slow in an area formerly worked into pillars, especially at a point traversed by a former road; and at the other extreme, rapid convergence occurs in coal formerly left as a barrier. The manner in which the convergence rate depends on the distance from the working face has also been observed (auth)