Mine excursion
sourced for the project, over and above the
103 000m3 of aggregate used for the road
layer works.
These quantities demonstrate the sheer
extent of the construction works that were
completed in such a short period, and
Visagie says that Jodan Construction’s
strong team on site also played a huge
part in helping the professional team
meet this onerous deadline by consistently
maintaining the required high-quality levels.
This is in addition to the significant
resources that the contractor deployed to the
project to keep works progressing according
to schedule.
For example, more than 70 tipper trucks
were on site to transport construction
material to the various work faces — an
extensive logistical undertaking that
required close and careful coordination.
Meetings were held almost daily
between representatives of the contracting,
engineering, and Exxaro project teams
to regularly assess progress made and to
anticipate and quickly solve challenges as
and when they arose.
Certainly, the hands-on approach
adopted by the client and its willingness
to assist in solving complications, and
excellent team dynamics between all
representatives of the professional team as
well as the contractor, also played a large
part in the successful outcome.
Innovative solutions for
complex challenges
One of Visagie’s critical functions on site
was to provide technical advice to the
professional team, and he is very proud of
the extent of innovation that was deployed
on this project to solve many challenges.
This includes working in a wetland through
which the new provincial and district roads
traversed.
A novel solution was devised to stabilise
the bases for the 14 large, 2.4m × 3m
stormwater structures that were installed in
this marshy terrain with rock grid, bidim,
rockfill, and 19mm and 6.4mm aggregate.
Another example of innovative thinking
was the use of impact compaction rollers
on as much as 80% of the road distances
to accelerate the treatment of large areas
located in commercial maize farmlands.
Impact rolling has the added benefit of
obtaining much better levels of compaction
at depth. Better compaction of the substrata
creates a stable platform to construct a
surfaced pavement structure highly resistant
to permanent deformation.
Notably, the private road features a
16mm micro surfacing, Ralumac. Ralumac
is a rapid-setting cationic modified
rubber bitumen slurry AC-E1 and known
industry-wide as a surfacing alternative
that facilitates fast construction. The
resulting surfacing is highly durable and
resistant to permanent deformation, like
rutting and shoving.
“It has been used extensively in the
country on public-sector road construction
projects such as those by the City
www.miningmirror.co.za
Marshy area filled with rockfill using end tipping.
of Tshwane Roads and Stormwater
Department. This was the ideal opportunity
to introduce the client to a more affordable
and longer-lasting surfacing product, the
performance of which will be monitored
as part of a trial period. The service life is
largely dependent on the aggregate type
used, but will likely last in excess of 10 years,
provided good-quality aggregates were
sourced,” Visagie says.
One of the challenges on this
component of the project was coordinating
construction activities on the private road
with the extensive haulage operations of
Exxaro coal mine.
The haul road serves many large rigid dump
trucks. A semi-automated traffic and access
control boomgate system was implemented
for the level crossing with the public road.
The road comprises a 150mm thick
base course, 200mm sub-base layer
and two selected layers. The contractor
deployed a state-of-the-art road recycler
for stabilisation to provide a consistently
homogenous mix, with cement bags
unpacked and squeegeed by hand to
assist in creating jobs via labour-intensive
construction practices, despite the fast pace
of construction required.
The provincial corridor caters to high traffic
volumes and this includes the many heavy
commercial vehicles that use the road and
abnormal loads that are transported to and
from mines and other industries in the area.
To maintain high road safety levels, the
bypasses along this route were built to
high pavement standards and illuminated
with solar studs and mobile high mast
lights, while extensive signage was
installed on both sides of the road to alert
traffic.
“We also had a very competent Exxaro
Resources safety officer on site. He went
to the extra effort of alerting all couriers
working in-and-around the area of the
bypasses. The contract team also installed
radar speed cameras typically deployed
by the traffic authorities. They flashed at
speeding vehicles, which slow them down,
and this proved to be a very effective
means of encouraging safer driving
behaviour,” Visagie says.
At the same time, a local emerging
contractor was appointed to construct a
1km section of the district road, gaining
valuable experience while working
alongside an established principal
contractor.
MARCH 2019 MINING MIRROR [17]