“Estimation of the Height of Complete Groundwater Drainage above Mined Longwall Panels,”

Author's Reply

“…The statement in Tammetta (), quoted by Pells (), refers to complete drainage of groundwater initially in storage in the collapsed zone, and the continued drainage of free water entering the collapsed zone from the disturbed zone.…”

“…Pells () states “with vertical downward flow one can readily have the situation of zero pore pressures, but without drainage.” Presumably Pells () is describing equilibrium flow (flow without change in, or in this case, without decrease in, storage). This is a trivial case of a more general transient process involving changes in storage, and is of limited use as an example; it occurs for the special case where system recharge satisfies system discharge.…”

“…Pells () uses an example referenced by him as being from “Terzaghi (1942),” as support for his argument. This reference could not be found, however, the example presented by him appears to be identical to the Figure 76e example in Terzaghi (), and it is assumed that this example is the intended one.…”

“…The statement by Pells () that a “fundamental assumption” has been made in Tammetta () is incorrect. The statement in Tammetta (), quoted by Pells (), is a definition.…”

“…I thank Pells () for the comments on my paper. This reply responds to the comments in the same order as they appear in that commentary.…”