Table 4.

Methodology and calculated volumes of the Brassington Formation

StepMethod
1Steetley Refractory Firebrick Company profile measurements converted from imperial to metric units
2Profiles re-scaled to 15 m intervals between 275 and 335 m OD
3Bases of the pockets contoured at 15 m intervals
4Difference between the pre-exploitation ground level and the contours of the base of the pockets calculated from 261 measurements at 25 m intervals along 5 borehole profiles. From this the mean depth of the complex was calculated.
5Volume of sediment estimated from the product of the area of an assumed circular footprint (of mean radius) and the mean depth of the Bees Nest Subsidence Complex
Volume (×106 m3)Results
10.5Vertical-sided complex to a sub-Brassington Formation surface at the elevation of Harborough Rocks escarpment (379 m OD)
11.270°-sided complex to a sub-Brassington Formation surface at the elevation of Harborough Rocks escarpment (379 m OD)
18.4Vertical-sided complex to a sub-Brassington Formation surface at an elevation of 450 m OD
21.870°-sided complex to a sub-Brassington Formation surface at an elevation of 450 m OD

The upper part of the table details the five steps used to quantify the volume of the Brassington Formation outliers over the entire basin. The lower part of the table gives four possible scenarios for the volume depending on the side-slope inclination of the pockets and the elevation of the sub-Brassington Formation surface.