Monontsha - A success story in holistic
environmental management.
When Impala Platinum encountered waste management and environmental
issues at their Rustenburg mine complex they resorted to an original, holistic
approach to the problems. The mine had a number of waste streams that
needed to be managed and they also wanted to attend to the rehabilitation of
the slopes of their tailings dams. Monontsha was an innovative answer to this
situation.
Established in 2004 as an empowerment project between Impala and the local
Luka community, Monontsha enjoys an ongoing contract with the mine currently
valued in excess of R6 million per year and provides employment for over 50
people across its’ process, transport and vegetation divisions.
The Process
Timber wastes in the form of redundant shaft supports and wood fibre from the
mineral extraction process are brought into the Monontsha complex. Here the
solid timber is shredded in a powerful chipper.
Sewage sludge is brought in from both the mines own treatment plant and from
plants operated by the local municipality. The materials are mixed together in
equal proportions and formed into windrows. Over a period of approximately
12 weeks the windrows are regularly turned and watered promoting the creation
of a quality organic compost.
The company currently produces around 900m3 of compost per month.
The windrows are regularly turned and
watered to encourage the natural
composting process.
The raw materials for the Monontsha
composting process. From top, shredded
timber from waste mine supports, wood
fibre from the mineral extraction process
and treated sewage sludge.
The company operates its own transport
division of trucks, plant and equipment.
The Rehabilitation
When ready for application the compost is transported to the slopes of the
tailings dams. After the slopes have been manually cleared of alien vegetation
the compost is applied at a rate of about 100m3 per hectare. It is worked into
the ground which is then seeded with a mixture of selected grass species.
This process not only stabilises the slopes, preventing erosion by wind and
rain, but also beautifies the area and encourages the return of insect and
eventually bird and animal life.
When the material is fully composted it is
transported to the slopes and worked into
the ground before seeding can take place.
Tailings dam slope showing completed
rehabilitation work. The next level will be
composted and seeded when it reaches
a height of approximately 3 metres.
Fully composted material ready to be
utilised for rehabilitation.
Rehabilitated slope after a single winter
season shown against levels still to be
attended to. Summer rains will quickly
promote healthy growth.
The Way Forward
Trials are underway to also utilise the compost in the growing of indigenous
shrubs and small trees which will be transplanted onto the slopes to further the
aim of returning the areas to a natural state.
A new vermiculture project is intended to eventually supply the company with
high quality vermi-compost which will be blended with the standard product.
The resulting premium organic compost will be marketed to local farmers and
growers providing additional income for the community.
An extension of the companies’
composting efforts, the vermiculture
project is showing encouraging results.
Telephone 014 569 1145
Indigenous trees and
shrubs grown with
Monontsha compost
will eventually be
replanted as part of the
slope rehabilitation.
Compost not used for slope rehabilitation
is screened to a fine consistency and
marketed to local growers.