Proposal for woodash application to Mud Lake within the "waste management area" at the abandoned South Bay Mine site / For David Porter, Talisman Energy Inc
Date
2002-07-22
Authors
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Publisher
Boojum Research Ltd.
Abstract
Wood ash has long been recognized as a valuable and safe additive to
agricultural soils. Composed primarily of calcium- and potassium-oxides, it also
contains major and minor elements common in the environment and yet essential
to plant growth. Field and greenhouse research have shown that it has a liming
effect of up to 90% of the total neutralizing power of lime. Almost by definition,
since ash is derived from the combustion of clean and virgin woods, it is not
offensive to the environment.
In summer 2000, 4 t of wood ash, generated in Ear Falls by Weyerhaeuser sawmill, was
applied on an experimental basis to the slopes of the recently enlarged Backfill-Raise
Ditch at the Abandoned South Bay Mine Site, which provides a pathway for seepages
from the underground workings. Lacking a ground cover, the contaminated slopes were
vulnerable to erosion. Experiments in the previous year, with one truck load of wood-ash
indicated that the wood ash would both raise the pH of the waste rock, and provide
nutrients to stimulate the growth of a terrestrial moss. In fact, this was accomplished. The
resulting carpets of moss in the cracks between the rocks stabilized the ground and
reduced the infiltration of the contaminated run-off into the waste rock of the mill site.
During the summer of 2001, with the approval of the MOE, approximately 100 tonnes of
wood ash were spread over Mill Pond, Mine site and on the Backfill Raise ditch slopes.
The results will be documented by fall 2002 but so far are very promising.
Concurrent with those terrestrial experiments, in May 2000, wood ash was added to
samples of acidic water taken from Mud Lake and Boomerang Lake, both of which lie
within the waste management area. The pH of Mud Lake is presently at 2.5; Boomerang
Lake is 3.0. The object of the experiment in two 1 m3
containers was to determine the
amount of wood ash required to raise the pH to 4.5, at which level phytoplankton and
microbial activity accelerate, to counteract acidification and promote biological
polishing, mainly for the removal of zinc.
Wood ash has two reaction components; it contains potassium oxide (1.6 % wt/wt),
which reacts immediately, and calcium oxide (11.4 % wt/wt), which settles with the
remaining inert materials in the ash, which is about 80% by weight, to the sediment of the
lake to be treated. From there it gradually releases its neutralizing capacity.
Description
Keywords
South Bay Mine, wood ash, Mud Lake, Waste Management Area, Boomerang Lake