update on sbm, page-38

Hi Folks, I have been following this with interest but am loathe to make any comments either way at this point. However, as anyone actually read the prospectus, in particular the following on Page 22............

"The previously announced target of producing at the rate of 450,000 ounces per annum by December 2008
is now expected to be achieved by the middle of the 2009 calendar year. The reasons for this change are
described below.

St Barbara recently optimised its mining approach at Gwalia, changing to a “bottom up” mining approach
of the ore body above the dolerite dyke (which first intersects the Gwalia ore deposit at approximately 1,100
mbs), from the “top down” mining approach proposed in the Gwalia feasibility study. This change will result
in greater longer term benefi ts for the management of the stress regime environment of the mine relative to
the requirements of the Gwalia feasibility study stress regime model. As a consequence of this change of
approach, the slower ramp-up of production will result in production from Gwalia Deeps of approximately
60,000 ounces in the 2009 financial year; a reduction of approximately 33,000 ounces compared to the 2006
feasibility study."

Can someone please provide some input on what is meant by "bottom up" as opposed to "top down", my understanding that all the hoopla was about the fact they had reached the 'top' of Gwalia Deeps, is this not already implying that the grades at the top were not as expected and that they will go even deeper before full scale mining commences??????, this would explain the blowout of the timeline.