Case Study: Hawk International

Essential testing regime ensured project success in Sierra Leone


In operation for more than 40 years, the Hawk Group employs more than 700 people worldwide, with a group turnover exceeding £70 million.

In Sierra Leone, Hawk International (Hawk) has worked with African Minerals Limited (AML) for more than three years. AML is a minerals exploration, development and mining company, and is currently developing and mining the world-class iron ore deposit at Tonkolili, together with its related rail and port infrastructure. The project is the largest employer in Sierra Leone, and is set to become the largest contributor to the country’s GDP.

Hawk was involved in both the development of the mine, and construction of the railway used to deliver the ore to the port, and on to the marketplace. Hawk provided plant, operators and management expertise to assist the AML project team with all aspects of the construction project. At its peak, the company had more than 200 items of equipment on hire to AML, and more than 400 expatriate employees on the roster.


AML had decided to further develop the rail and port infrastructure at Pepel port to handle the expected additional tonnage from the mine. The rail carries the ore from Tonkolili mine to the port, and is AML’s only means of exporting the ore to market.

The Tonkolili site in Sierra Leone
The project at AML’s Rofanye quarry involved the provision of rock and aggregates for the rail and port construction works. It required rock blasting and crushing from Rofanye Quarry, and at the Tonkolili site, for future expansion works of the mine and to provide additional space within the tailings area.

The Rofanye works involved the removal of more than 200,000M2 of overburden to uncover the rockhead, followed by rock blasting and crushing to various specifications. The three-year rolling contract had an annual minimum requirement that varied from 543,720 to 1,291,033 tonnes of product; the final total was 2,656,686 tonnes. These products included rail ballast, G6 (200mm down material for rock fill), G4 (sub-base type material), <19mm single size rock for concrete works, <6mm (crushed sand) for concrete works, and crusher dust to be used as sand. A quantity of blast rock and blockstone was to be provided direct from the blast face.

As in any quarry, the rock varied in its composition, which was a cause for concern. It was critical that the raw material could be accurately and quickly assessed, allowing for its best use.

The main challenge was to ensure the raw materials were tested and approved on a daily basis, which involved maintaining a close working relationship with the Crushing team, and especially the Production Manager.


The laboratory equipment, and the Celtest team (Mark Culbert and Nigel Wager), was mobilised in April 2013. Prior to the team’s arrival, Hawk had constructed a laboratory to Celtest’s specification, including air conditioning and a fully covered sample preparation area.

Site sample preparation areasAfter the team arrived on site, the laboratory was fully commissioned within a short time, allowing rapid assessment of raw materials by testing to the specifications as outlined. The team was also instrumental in selecting the raw material’s best use as a product.

As Darren Cumming, General Manager for Hawk International, says, ”The Celtest team was essential to the project’s success, not only with the testing regime to ensure that products were within specification, but also understanding the various specifications that we had to work to. Some products were to UK specs, while other products were designed using South African specs; it was essential that we understood these requirements and produced good quality material.”

Celtest calculated and supplied the equipment required for the on-site testing, and also brought in the laboratory manager and assistant to do the testing.

Nigel Wager at AML's Rofanye quarry
Being a relatively small laboratory, it was essential the expatriate staff could resolve any possible problems and issues. These included work-related problems, and the entire experience of working 3500 miles away from home. It was essential that the staff could ‘think outside the box’ when requests for certain information were made by the client. It was simply not possible to contact a supplier and pick up specific equipment as required, because the long shipping times would have prevented progress. The team also trained local workers to assist.

 Darren says he was pleased there were no issues, with subsequently few affects on production. He adds: “Once the testing regime was installed, it worked very well and we found it easy to work with the laboratory team. Results were issued quickly and re-screening of any failures was not a major issue. The staff proved to be very inventive in the manufacture of items to allow testing to go ahead.”

Other challenges the team needed to overcome were the extreme heat and rain during the wet season, and the various different languages among the various teams. However, as Darren adds, “Language barriers were quickly overcome once we all understood what Mark was saying – and as long as he spoke a bit slower, because the ‘scouse’ accent was then not quite so pronounced.”


Darren comments, “The Celtest site staff was always easy to deal with, and any support required from Celtest’s UK team was received quickly and was effective.” Darren adds that when there was some financial difficulties due to late payments from the client, the inevitable knock-on effect was satisfactorily solved with the co-operation and understanding of the UK team.

Commenting on the UK’s team integration into local Sierra Leone life, Darren says, “The Celtest SL team became a firm part of our own Hawk SL team, getting involved in various charities and other public relations work that seems to be a part of any overseas project. Mark was part of the Hawk team that competed in the Makeni Marathon, and he turned in a very creditable time and raised some money to boot. Both he and Nigel were involved in football matches organised against local teams – the fact that Mark was an Evertonian didn’t go against him in these matches!”

Darren concludes, “Celtest proved to be an inspired addition to the quarry team, as they provided everything required to successfully manage the specification, which in turn allowed Hawk to do what we do best without worrying about these issues. We would not hesitate in requesting them again should more work arise.”


Site Testing

On-site materials testing from Celtest

Laboratory Testing

Laboratory materials testing from Celtest


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