Zublin is one of the biggest contractors in Chile and has developed a wide range of projects which involves mining, energy, infrastructure, civil engineering works and construction. Zublin was awarded a new mine development contract for three years in El Teniente mine, and as part of this development they are required to spray around 2,500 cub mt of concrete monthly, meaning four sprayers and 16 operators are needed.
Since the mine development is under high rock mass stress, the owner Codelco pays extra attention to the quality of the sprayed concrete and thoroughly monitors the sprayed concrete process. As with many contractors Zublin pays close attention to quality issues, amount of rebound and consumption of accelerator.
Normet worked full time with the Zublin team at the site, firstly with their actual process evaluation and then in the design of an improvement solution recommended in each stage of the sprayed concrete process. Main opportunities for improvement were a higher-than-ideal water cement ratio in the concrete mix, an improvement opportunity of process knowledge by supervisors and sprayer operators, a higher-than-anticipated percentage of rebound, a higher-than-expected dosage of accelerator, all of which combined to produce a significant upside opportunity for sprayed concrete quality and reduction of consumption of materials.
With Zublin’s encouragement, Normet designed a sprayed concrete process training program. The training program covered all stages of the process, starting with the aggregates selection for the concrete mix and ending with quality controls of the sprayed concrete on site.
The program was designed to educate the supervisors and operators, including the batching plant, transmixer and sprayed concrete operators and internal quality control personnel. The Normet simulator was used to evaluate the operators’ performance and to further develop their skills. The program was designed to be executed on site for a total amount of 36 persons, and for a duration of four months.
After four months of hard work, Normet together with the customer team was able to achieve an important reduction on the process cost, and an important increase on the sprayed concrete quality. Rebound was reduced on average by 17% and accelerator consumption decreased by 3%.
Continual, incremental improvements in performance are expected downstream as the Nozzlemen become adept with their new knowledge and skills.