Cement, ready-mix concrete and aggregates company AfriSam is focusing on producing high-quality cements, concretes and aggregates, as well as offering a timely, reliable service to clients, amid difficult economic and construction-sector times, says AfriSam construction materials North regional manager Zielas du Preez.

AfriSam took journalists on a tour of its Jukskei granite quarry, in Midrand, which was founded in a rural setting in the 1950s but operates in a built-up and fast-developing area since 2016, to showcase its quality control, safety and environmental protection initiatives.

The company highlighted the measures and precautions it takes to ensure that dust and noise are within compliance levels, as well as blasting technology and techniques used to control the vibrations and mitigate any danger during blasts.

The company uses water from the base of the quarry to suppress dust on the haulage roads, which also drains back into the quarry, water sprayers in the crushing equipment to reduce dust liberation at start-up, and initiatives to reduce noise, such as ensuring materials are discharged on top of an existing bed of material in the feeders, as opposed to discharging material on top of bare metal, which helps to reduce noise.

The quarry is next to a busy helicopter pad, and it sends communiques to warn of potential dust and when a no-fly zone is in place above the quarry while a blast is carried out. Similarly, the Jukskei quarry team communicates constantly with all the stakeholders and building managers of its neighbours, which include industrial warehouses and corporate offices.

Further, the mine engineers have worked to conclude all the mining on the stopes on the northern faces that are nearest to its neighbours, and quarrying will proceed mainly in an easterly direction, which will limit the impact on neighbours from blasting.

“We use electronic blasting technology, which, while more expensive than conventional blasting technologies, enables us to simulate and then design the blasts to ensure that vibrations are kept below 22 mm/s, or below 25 mm/s if the frequency is above 14 Hz, and below the 125 dB noise limit. However, we design our blasts to be well below these limits,” says Du Preez.

The company adheres to US blast management and consulting standards, and all its operations are managed in accordance with ISO 9001 quality management standards, he highlights.

Further, the company takes precautions to limit fly rocks and noise generation during blasting, such as placing materials in and on top of blast holes – called stemming – and digitally simulating blasts to verify blast designs and expected parameters, which helps it to control blasts and their impacts.

“Effective chemical crushing reduces mechanical crushing efforts, but we also have to ensure that it is safe for our people, our neighbours and our equipment. We use advanced blast simulation software – as well as the advice of an independent blast engineer – to tread this fine line,” he says.

Ready Resources

The Jukskei site also has two ready-mix plants, which supplies developments in Sandton and Midrand, as well as the Gauteng region, says AfriSam North and Central operations manager Kevin Naidoo.

He showcased the technical accuracy of the ready-mix batch plants, as well as the controls in place to ensure that the correct ratios of ingredients and additives according to the engineer’s specifications are mixed and dispatched for clients.

AfriSam has a central fleet management and control room to ensure that the trucks are loaded and dispatched to clients timeously, as well as to manage any client delays and ad hoc requests.

AfriSam Ready-Mix Gauteng, North West and Mpumalanga regional manager Russell Wearne highlights the importance of the company’s ready-mix operations to use cement and aggregates from its operations. AfriSam is a member of the Southern African Ready-Mix Association.

“Market conditions are currently severely depressed. We can produce more than four-million cubic metres a year of ready-mix, but we are producing far less at the moment.”

AfriSam is focusing on ensuring reliable supply of high-quality products during the tough times. It has proven capabilities to do specialised mixes to meet demanding project specifications, such as the PwC tower in Waterfall City, in Midrand, which required that the concrete be poured into the shuttering that was continuously raised to build the central tower, he says.

“Our in-house research and development capabilities stand us in good stead to develop specialised mixes required by civil engineers, developers and mining houses, and we are a preferred supplier for most of the regional large-scale developments.

Pricing wars will only lead to poor-quality products and projects, and AfriSam is focused on ensuring that we develop our personnel’s technical skills in preparation for when development accelerates again,” concludes Wearne.