Hot and cold asphalt manufacturer Much Asphalt supplied over 1,1- million tons of asphalt over 30 months, ending in October, to the South African National Roads Agency Limited’s Gauteng Freeway Improvement Project (GFIP).
When the company completes its supply contracts for the GFIP in September 2011, Much Asphalt will have supplied asphalt worth more than R1-billion to the project.
“No other asphalt supplier in South Africa could have achieved what we did in the past two years. Through significant investments in people, plant capacity and quality control systems, we have been able to supply 15 joint venture contractors on various GFIP sites by deadline. With equally challenging supply projects, such as the N1, also under way in the Western Cape, we had to ensure that we provided equal and adequate focus in both regions,” says Much Asphalt marketing director John Onraët.
The company had to overcome a number of challenges to provide the large quantities required for the GFIP on time and to specification. Significant challenges included the continuity of raw materials supply, delivery logistics, the potential delays caused by bad weather, the possible increase in demand, the risk of experiencing problems with products, mixing plant availability and continuity of supply to other clients.
Much Asphalt believes that efficient project management is essential for its seven plants in Gauteng and the neighbouring provinces, with a combined capacity of 1 100 t/h, which are involved in supplying the GFIP.
Leadership was a priority at the outset of the GFIP contracts, with a steering committee assembled to lead the project. Dedicated contracts managers were given responsibility for regular shifts, as well as additional shifts during peak demand times, while a logistics manager was appointed to focus exclusively on deliveries from Much Asphalt’s plants to the GFIP sites.
Daily shifts were increased from two to three at all seven plants and included two production shifts and a plant maintenance shift. This was important in reducing plant breakdowns and ensuring consistent product quality and meeting demand from the GFIP, as well as demand from other clients. Some downtime was experienced during peak demand periods, but was mitigated by rerouting and rescheduling plant supplies.
Continuous communication about progress and quality is ongoing and includes daily meetings with the contractors and consulting engineers.
Much Asphalt says that strong long-term relationships with suppliers have resulted in few delays caused by material supply issues on the GFIP.
“The company ensures that it replaces outgoing product with raw material daily. Constant contact with the refineries is key to ensuring that the bitumen supply is managed, as well as with sand and aggregates, and fuel and binder suppliers,” adds the company.
Further, Much Asphalt’s process control laboratories went into overdrive when undertaking quality testing of both raw materials and finished products for the GFIP.
“It has been difficult to keep up with the quality of incoming aggregates, owing to the sheer volumes arriving at the mixing plants, but interlaboratory comparisons and constant calibration have helped to ensure consistency.
“Through dedicated leadership, good relationships with suppliers and clients and constant attention to product quality, we are confident that we will complete our GFIP commitments successfully and on time,” concludes Onraët.
By John Onra ; Process Controller
Coal Fired Asphalt Plant
The invention comprises a coal-fired burner system for use in a drum mix asphalt plant or drum dryer used for producing asphalt paving composition.
Coal to fire the burner is ground to a -200 mesh size by an air-swept rotary impact mill, and a classifier at the exit from the mill controls the size of the particles leaving the mill.
The pulverized coal particles are recovered from the exhaust airflow exiting the mill by a fiber filter collector and temporarily stored in a small surge bin.
Coal is metered from the surge bin into a primary air conduit leading to the burner.
The availability of a small but ready supply of coal in the surge bin provides quick response to a need for increased coal while avoiding the dangerous storage of large quantities of pulverized coal dust. As the weight of coal dust in the surge bin decreases, control circuitry provides for the processing of additional coal to maintain a ready supply of processed coal in the surge bin.
Use of a burner having swirl vanes to create a short cyclonic flame pattern permits the burner to be mounted directly in the upper end of the drum without the need for a separate combustion chamber, but without sending a long flame into the mixing area of the drum where liquid asphalt is introduced, which would cause a fire hazard and pollution problem.
United States Patent 4638747
Coal to fire the burner is ground to a -200 mesh size by an air-swept rotary impact mill, and a classifier at the exit from the mill controls the size of the particles leaving the mill.
The pulverized coal particles are recovered from the exhaust airflow exiting the mill by a fiber filter collector and temporarily stored in a small surge bin.
Coal is metered from the surge bin into a primary air conduit leading to the burner.
The availability of a small but ready supply of coal in the surge bin provides quick response to a need for increased coal while avoiding the dangerous storage of large quantities of pulverized coal dust. As the weight of coal dust in the surge bin decreases, control circuitry provides for the processing of additional coal to maintain a ready supply of processed coal in the surge bin.
Use of a burner having swirl vanes to create a short cyclonic flame pattern permits the burner to be mounted directly in the upper end of the drum without the need for a separate combustion chamber, but without sending a long flame into the mixing area of the drum where liquid asphalt is introduced, which would cause a fire hazard and pollution problem.
United States Patent 4638747
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