African Minerals Limited (AML) is the company behind the development and mining the iron ore deposit at Tonkili. The project is the largest employer in Sierra Leone, and is set to become the largest contributor to the country’s GDP.   


The varied rock composition at the quarry project needed to be carefully assessed, and tested to critical specification; assistance was also required with selecting the raw material’s best use as a product.       


Celtest established a testing regime, equipment, and essential on-site staff to ensure that products were within the various UK and South African specifications. It also trained local workers to assist in the testing process.  


Celtest proved to be an inspired addition to the quarry team, providing everything required to successfully manage the specification.


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 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, was mobilised in April 2013. Prior to the team’s arrival, a laboratory had been constructed to Celtest’s specification, including air conditioning and a fully covered sample preparation area.
After 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 the client, 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. 

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.  

The client 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.


Client feedback, “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.” 

Commenting on the UK’s team integration into local Sierra Leone life,“The Celtest SL team became a firm part of the project team, getting involved in various charities and other public relations work that seems to be a part of any overseas project. 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 us to do what we do best without worrying about these issues. We would not hesitate in requesting them again should more work arise.”