Page 59 - 00 Volume 5 The Mine

directly affect the workings but it necessitated section of lake.
extensive investigations and repairs costing between First a large hole was scooped out of the
£80,000 and £90,000. Supplementary stopbanks original stop-bank and the dredge constructed in it.
were built to provide additional protection for the Upon completion of the dredge the water was let in.
workings. Experts in the study of soil stability The dredge had a suction hose that drew water and
consider that the protection works now provide an mud into it and along a floating pipeline and out into
adequate margin of safety. Despite this setback
Kimihia opencast mine remains one of New Zealand's what remained of the once-large lake.
most important coal producers. While the dredge was being constructed the
Coal was also carried out of the district by rail earth-moving machines were constructing a very long
and over the narrow, but well-gravelled access road stop-bank enclosing the area to be exposed. This
that had been put in about 1944 to service the village. basically completed the cutting off of the southern
From the lake shore the road curved up a short but section of the lake.
steep hill past the school and, during the winter, the Control gates were built in the northern bank to
heavily laden coal trucks made hard work of the hill control the inflow of water to keep the dredge afloat.
and regularly interrupted the schooling of the pupils as At intervals along the stop-bank there were suction-
they ground past on the neighbouring road in first pipe stations that could be connected up to the
gear with exhausts belching and engines roaring. dredge as it moved around its pond. A cat-walk was
On frequent occasion the trucks actually spun built along the top of the floating pipeline to give
away the gravel covering over the clay base of the access to the dredge as well as providing a support
hill and they could not progress until a bulldozer for the diesel fuel pipeline to the dredge's motors
from the mine came to assist them. and pumps. This floating piece of machinery was
This happened far too often for the mine serviced by a motorboat and a barge.
management and a lower grade road was cut up the The cutting head on the dredge was on the end
hill in an arc around the offending area. of a long boom that could be raised and lowered and,
The trucks still screamed their protests as just to the rear of the cutting head was the vacuum
they crawled up and past the school but were unit that drew up the resultant slurry.
uninterrupted in their journey. As the dredging got deeper it was found
In 1956 it was decided that a world first for necessary to add booster pumps to get the material up
an opencast mine in dredging was to be attempted and over the dam. Also the dredge was stopped at
further out in the lake to get at the seam as it shelved periodic intervals to remove the huge stumps and
down deeper to the north. The importing from trees buried in the old lake-bed.
Australia of a powerful dredge was undertaken and it The dredge was kept afloat by a sluice-gate in the
was used to chew up the lake bottom and pump the dam regulating the flow of water back into the
slurry out over the stop-bank and into the remaining working pond.

The dredge being removed from the mine on a specially imported transporter onto the banks of the Waikato

River.