Hillock s “Sump”
Conclusions of a pumping operation conducted by CCPC et al 23 4 03
A sump exists at the end of a level in Hillocks Mine Monyash known to the explorers
as the S west Cross Cut Sump. Access was by SRT down the 200’ Whalf Engine
Shaft. Pumping equipment etc was lowered and raised by winch for speed and
convenience. This enabled the whole operation to be completed in approx six hours
with a workforce of five.
5
Evidence of early mining can be seen in the form of hand picked levels throughout the
workings at different horizons though most are victims of reworking with gunpowder.
A clear example of this is illustrated in the main cartgate from the engine shaft
chamber to the above cross cut, where a complete hand picked level is intact in the
roof, the floor having been blasted out with powder to form the main gate, a more
detailed description can be found elsewhere. The cross level consists of a blind stope
like working, quite low, due to reworking and backfilling with deads. Near the end,
the floor dips down steeply due to a decrease in the depth of infill, estimated at 3m,
based on observations in the dewatered forefield.
This “dip” is permanently flooded to almost floor level, and the object of the pumping
operation, the exercise being to establish if the level continues below the flooded roof.
As the water level dropped a gently dipping bedding plane was revealed with a large
quantity of water issuing into the sump along the bedding- the reason for the flooding.
As pumping progressed deads were removed to a depth of 2.5 metres to reveal a
section of original floor with the forefield sloping back down the “dip” towards the
level.
Below the normal water perch, surprisingly large and uniform shot holes approx 24”
long and 1 ¼ “ diam. were noted driven vertically downward. Contemporaneous holes
have not been seen, at least by the writer, in other parts of the mine, and probably
represent late stage reworking with compressed air drilling.
Earlier work in the roof can be seen that represents the original driveage, with shot
holes of 7/8” diam, possibly dating from the 1750s or earlier, given the history of this
place. It will be noted when descending the engine shaft that yet another size of drill
hole is in evidence i.e. 1” diam. Which should allow accurate dating of the shaft.
Conclusion.
A calcite vein can be seen in the centre of the heading with a vertical groove picked
out. This may have been a lead scrin that was followed in the hope that it would belly
out with depth., a reasonable speculation. However in this instance no such vein was
found.
Len Kirkham CCPC. PDMHS
