Inside Rwanda’s sole mineral testing lab

As economic planners search for ways of narrowing the gap between the country’s exports and imports, trade in formerly little-known minerals such as Coltan, Cassiterite and ambrigonite has emerged as a potential solution with total value of minerals exported during the first half of 2013 up by 77.7 per cent.
Kevin Terry analyses some mineral samples. Sunday Times/Courtesy
Kevin Terry analyses some mineral samples. Sunday Times/Courtesy

As economic planners search for ways of narrowing the gap between the country’s exports and imports, trade in formerly little-known minerals such as Coltan, Cassiterite and ambrigonite has emerged as a potential solution with total value of minerals exported during the first half of 2013 up by 77.7 per cent. Moses Opobo visited Rwanda’s only mineral testing facility and looks at the process of making the minerals ready for the market.

IN THE mining sector, it is important that accurate information be obtained on the grade of the minerals that are mined and subsequently traded. 

Information regarding the grade of a mineral enables it to be traded at a fair price. It is the responsibility of samplers and assayers to take the samples and perform the analyses in an accurate and professional manner. 

In Rwanda, this task falls squarely on the hands of Alex Stewart International Rwanda Ltd, the country’s sole independent sampling and assaying organisation.

Located in Gikondo, near the old Inyange Industries plant, the company is a local subsidiary of UK-based Alex Stewart International, global sampling and assaying conglomerate.

In its specialised laboratory, the company tests samples from local mining companies, cooperatives and individuals to determine the nature, quality and quantity of the ore. The analytical techniques available include wavelength-dispersive and energy-dispersive X-Ray fluorescence spectrometry, inductively coupled plasma, optical emission spectrometry, atomic absorption spectrometry, and wet chemical analysis.

The company’s managing director, Norman Mwashi explains that the firm undertakes two primary activities: sampling, and analysis. 

“At the sampling stage, clients with mineral samples or shipments for sale, bring them to us to determine the grade. Based on this, they are able to establish the monetary value on the market.”

He explains that at other times, it is prospective buyers who contact the company to ascertain the quality of ores before they place orders with suppliers. “After we have tested and graded the samples, we issue the client with a certificate of analysis, which is basically a document that verifies the quality of the material,” Mwashi explains.

At the analysis stage, submitted samples are taken to the laboratory for milling. “This produces a fine, homogeneous powder, which is truly representative of the original sample,” adds Mwashi.

The standard procedure is to analyze this powder by X-Ray fluorescence spectrometry. This is a versatile technique which is rapid because it is not necessary to get the sample into solution. The powder is blended with a special chemical called a Flux, which enables the sample to be melted in a furnace to produce a uniform flat glass disc known as a bead. Other chemicals can be added at the fusion stage to enhance the fusion process and remove the interfering effects of the other materials in the sample - the matrix.

The company handles any kind of mineral concentrate or ore, but by far the most common samples are those of Cassiterite (an ore of tin), Coltan (an ore of tantalum), and Wolframite (an ore of tungsten), which are all relatively abundant in the country. 

According to the National Bank of Rwanda’s Monetary Policy and Financial Stability Statement for August 2013, total value exports for the mining sector increased by 77.7 per cent in the first half of the year. This was largely attributed to the value of Coltan exports that went up 191.0 per cent, Wolfram 28.8 per cent and Cassiterite 15.5 per cent.

The key minerals currently being mined and traded in Rwanda are; cassiterite, wolframite, Coltan (colombo-tantalite), and gold. Other minerals include ambrigonite, beryl and semi precious stones such as tourmaline, topaz, corundum, chiastorite, amethyst, sapphire, opal, agate and flint.

Construction materials which can be used in their primary state or given a higher value are abundant. These include; amphibolites, granites and quartzites, volcanic rocks, clay, sand and gravel.

Industrial resources such as dolomite, industrial sand (glass and foundry), kaolin (for ceramics and paper), limestone (for cement), quartz and feldspar exist in substantial amounts. 

While Alex Stewart International offers analytical services to the mining sector, it is processing companies like Mineral Supply Africa that further upgrade the minerals by reducing the impurities until a high grade concentrate is produced. 

Mwashi notes that on average, the company handles about 20 samples per day, although previously the number doubled. 

He attributes the reduced figures to an international ban on conflict minerals that barred sampling companies from handling “conflict minerals”. 

“Before the ban,” explains Mwashi, “we received samples from all over the region and beyond. After the ban, we now accept only samples from Rwanda.”

As a regulatory measure, the Ministry of Natural Resources actually tags all minerals from local mines, complete with the tonnage. As Mwashi further explains, “We only sample material that has been tagged, and even when you take your shipments for export, the importing country looks out for this tag, lack of which is tantamount to fraud.” 

According to Kevin Terry, an assistant chief chemist, “The whole point is to ensure that minerals that are sampled and sold do not come from conflict zones. The idea is to stop the abuse of people in mining areas.”

“Apart from tagging, dealers have to exercise due diligence and operate according to the Organization of Economic Development guidelines. This includes things like no use of child labor, and no physical abuse meted out to mine workers.” 

As a chemist, Kevin’s work calls for an analytical mind, an aptitude for scientific inquiry; a demonstrated interest in the environment, especially geology; a medical certificate of fitness, and good inter personal skills. He also has to be systematic and neat, and conduct himself with an air of responsibility. 

The work further calls for an exceptional degree of concentration and accuracy, and one must constantly update themselves with advances in the field. 

These characteristics apply to many of the employees, and attention to detail enables them to perform their duties in a professional and fulfilling manner. Many times, workers find themselves having to put in extra hours to complete tests and analyses so that the customers’ expectations are met.

Kevin and Mwashi work for the company on expatriate terms, both having previously worked for Zambia Consolidated Copper Mines. Apart from a private consultant, Jimmy Wilson, the rest of the staff is locally sourced, with three economics and two chemistry graduates. In all it employs twenty two people, up from just six when it opened its doors in 2006.

Working conditions in the facility vary from pleasant air-conditioned laboratories to hot, dusty and physically demanding conditions. One thing that is impossible to miss is the clean, cool and quiet environment that prevails in the labs. This is done to ensure a stable environment for the lab’s sophisticated equipment. It is also to ensure accuracy and reproducibility of the results produced.

In these labs, various chemical processes such as fusion procedures and wet chemical methods are applied to determine the level of trace elements in mineral samples, a procedure that requires an exceptional degree of accuracy.

The results obtained from the work of the assayer and sampler helps organizations or clients to plan current and future operations more efficiently.


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