ASM in Uganda provides a source of livelihood for almost 200,000 women and men (Hinton et al., 2011), over half of which are engaged in production of industrial minerals to serve the construction industry demands for the country’s rapidly growing population.
The women and men miners generally use basic tools such as pick axes, hammers, shovels, hoes etc. to extract a wide range of minerals though out the whole country. These activities are predominantly informally organized or disorganized, un-mechanized and often characterized by hazardous working conditions, lack of planning and issues related to child labour, poor health conditions and gender inequalities. Most often women and men enter the ASM sub-sector as it may be the most financially lucrative, most viable or sometimes the only livelihood option.
For this study, the commodities mined from the active ASM mining districts were identified and selected for field investigations (Figure 2). The teams visited the gold, tin, wolfram, and iron ore mining sites for the High Value Minerals and Precious Metals, and salt, sand, dimension stones and construction materials (granite, shale and quartzite), pozzolana, limestone and marble for the Low Value Minerals and Materials.
Detailed analyses of historic and recent information on active and abandoned artisanal gold mines and alluvial workings indicate that ASM dominates the gold mining sector in Uganda (SOMO and CRSS, 2016). The gold mining communities are widely spread out and are hosted by the Neoarchean Busia-Kakamega granite–greenstone belt in the South Eastern part of Uganda, the Paleoproterozoic Rwenzori fold belt in Central Uganda (e,g, Mubende, Mityana areas), the platform sedimentary rocks of the post Rwenzori fold belt (e.g. Buhweju, Mashonga, Kitaka areas), the reworked Archaean basement rocks and/or in the upper amphibolite–lower granulite facies rocks of the Neoproterozoic Mozambique fold belt in North Eastern and Western Uganda and in the Northern part of the Karamoja region.
Other areas in Uganda where alluvial gold mineralisation and/or shallow gold workings are reported comprise the Kitgum area within the Aswa shear zone in Northern Uganda, the Western Nile area which represents the Western extremity of the Bomu-Kibalian shield of NE Congo, and the Kabale-Kisoro area hosted in the Mesoproterozoic North Kibaran fold belt in South Western Uganda.
In 2008, at least 20,000 ASM miners were engaged in gold mining mostly in the Busia Greenstone belt, Mubende-Singo gold fields, the Karamoja Region in the East and Northeast as well as in the Kigezi and Buhweju-Mashonga goldfields across the West and Southwest of the country. A UNEP study in 2009 indicated that this level had increased by 20-40 per cent in 2009 and therefore one can conclude that there are around 60,000 miners involved in gold ASM in 2016.
The Tin province of Uganda (all the cassiterite deposits known in Uganda) is hosted by the Mesoproterozoic North Kibaran fold belt which is composed of metamorphosed clastic sedimentary rocks, to synkinematic, foliated to isotropic porphyritic and pegmatite granite attributed to the North Kibaran Igneous Province (NKIP; Harma et al. 2011). The system predominantly consists of argillites with arenites and silty rocks regularly distributed as thin bands throughout and Cassiterite (SnO2) is confined to the shales and sandstones of this system. Tin occurs in elluvial, detrital, pegmatitic and hydrothermal vein deposits.
Tin mining has been known in S.W. Uganda for over 70 years now. This mining however, concentrated on large veins and their immediate alluvium. Work on the industry started as far back as the 1920’s. In 1925 the first deposit at Kikagati was discovered, Mwerrasandu in 1926, Kaina in 1927 and Nyinamaherere (Figure 14A) in 1928. Tin enjoyed monopoly of Uganda’s mining sector until 1931 and this was followed later by a Tin boom in the 1960’s and 1970’s favoured by good world prices. During the boom, 22% of the total Cassiterite exported fetched $2,786,781 representing 56% of the total earnings from tin exports.
Tin production in Uganda has been largely on small scale both for underground and surface working. Tin was however first produced at Mwirasandu that was discovered in 1926 and production started the following year. Production in Kikagati started in 1929 (Galimaka, 1994). Mwirasandu mine has a large pile of coarse tailings with an estimated quantity of 120,000-135,000 tonnes while fine tailings dump has 195,000 – 210,000 tonnes.
Wolframite in Uganda is found in two regions; the south western Uganda and the Singo area in Mubende. The major former wolfram producing mines in Uganda in 1960s to early 1970s were Kirwa, Ruhizha and Bjordal in south western Uganda. Tungsten, also known as Wolfram, lapis ponderous or Heavy Stone, has highest melting point of all elements except carbon – sources in scientific literature vary between 3387°C and 3422°C. It also has also excellent high temperature mechanical properties and the lowest expansion coefficient of all metals. A temperature of about 5700°C is needed to bring tungsten to boil – which corresponds approximately to the temperature of the sun’s surface. With a density of 19.25 g/cm3, tungsten is also among the heaviest metals. Its electrical conductivity at 0°C is about 28% of that of silver which itself has the highest conductivity of all metals.
Iron ore being rocks and minerals from which metallic iron can be economically extracted means that, the ores should be very rich in iron oxides. Usually the ores occur in form of magnetite, hematite, goethite, limonite and siderite. Magnetite and hematite are the conventional ores that are utilised in steel industry, the world over, due to their superior quality and easy to process nature, as opposed to the unconventional ones.
Uganda is endowed with conventional iron ore reserves in form of hematite and magnetite, although, unconventional occurrences also exist in south western part of the country. Despite this, there has been very limited production of iron ore in Uganda to date, mainly for use as an additive in the steel scrap smelting in Jinja and for special cement by Hima Cement.
Iron ore in form of hematite occurs at Muko and Butare areas, in Kabale district and in Kashenyi, Kyanyamuzinda and Kamena areas in Kisoro district, where iron ore occurs in lenses and as scattered boulders in these areas. Similar hematite iron ore occurs at Mugabuzi in Mbarara district and in Nyaituma in Hoima District.
In form of magnetite, Iron ore occurs at Sukulu in Tororo district, Bukusu in Manafwa district, at Toror in Kotido district, and at Napak in Napak district. In general, magnetite in Uganda is associated with the carbonatite complexes.
Iron ore mining in Muko is done using local tools such as hammers; pick axe, chisels and unskilled labour. During our visit in Kabale we managed to go up in the hills of Ahamuguha in Gwara village and there we found an open pit (Figure 17) owned by one Master Benon. We luckily found the quarry manager Mr. Byamugisha Charles who narrated that in a day they load 4 trips of iron ore (6 tonne truck). The mine employs more than a hundred 100 people and out of these 20 are women.
Iron ore mined from this area is purchased by Steel Rolling Company which is further transported to its various factories in Kampala and Jinja. Mr. Byamugisha added that a tonne of iron ore costs 80,000 Ugandan Shillings. However he complained about the impassable roads and poor means of mining.
The largest mineral water reserves are the brines and evaporites of Lake Katwe, saline Crater Lake in the Western Rift Valley in south western Uganda, on the northern edge of Lake Edward in Kasese district.
Salt for human and animal consumption has been extracted on a larger scale from the floor of crater lakes at Katwe and Kasenyi in Kasese district for many centuries. Recent research (Kirabira, et al. 2015) over 15,000 people are employed in local salt extraction activity of whom over 75% of the labor force is provided by women, operating in over 10,000 salt pans, making salt extraction the major economic activity in this area.
Salt, at Lake Katwe, exists as a mixture of sodium and potassium chlorides, carbonates, bicarbonates and sulphates, with lesser amounts of gypsum (calcium sulphate) and traces of bromides and other constituents. Total reserves of 22 Million tonnes of trona with mixed salts have been estimated at Katwe. 50,000 tonnes per annum could be produced for at least 10 years before any decline would become evident. The current method of production is based on solar evaporation in ponds (Figure 18A) and the product is crude (Figure 18B) due to mixing of the salts during fractionation and crystallization as well as with mud at the lake bottom.
Salty water of Lake Katwe is posed by the great percentages of impurities that are fundamentally not desirable in common salt such as calcium, magnesium compounds present in significant quantities. The challenge is faced by the current mining and processing of the ore as these impurities such as clay, organic matter, calcium and magnesium compounds need to be removed.
In 1975 a plant was constructed in the Katwe deposit and worked for a few years until it failed due to corrosion of heat exchanger tubes. Attempts to repair were unsuccessful and the plant has since remained in inoperative (Figure 18C). The challenge now is devise feasible extraction technology that augurs well with the chemistry of the salt of Lake Katwe to tackle the corrosion issue, so as to engage large scale commercial production to produce edible salt.
Sand is a general term used for broken granules of minerals or rocks, technically between 0.17 to 2mm in diameter falling between silt and gravel in a spectrum of sizes. It can be used in a wide range of industrial processes such as construction materials (mixed with water and cement for brick laying and plastering), glass making, as fill, and to create molds and castings, depending on the quality of the sand.
So far, in Uganda, sand has been mainly utilized in building and construction industry as part of concrete material other than uses mentioned above, yet there are promising deposits of glass sand suitable for such commercial purposes at the showers of Lake Victoria.
Glass sand is associated with narrow Quaternary to Recent beaches along the shores of Lake Victoria and some lake Victoria Islands contain deposits of glass sand at several locations including: Kome Island (Buvuma district);
- Diimu (Rakai district),
- Katosi in Njeru,
- Bukakata and Lwera (Masaka district); and
- Nyoka-Nalumuli Bay (Mukono district).
It should be noted however that all over the country, sand is mined from almost all the rivers and streams to serve the local construction industry by both ASMs using hoes and shovels and medium scale construction industry using excavators (Figure 20 A and B). Sand production simply involves digging and loading into trucks. Value however can be added by sand selection and screening since different sand types are priced differently.
The price of sand varies from region to region and largely depends on the grade and quality. The highest quality (99.95% SiO2) glass sands have been mined from Kome Islands and exported to Kenya. At Diimu and Bukakata beaches, over 2 million tonnes of good quality sands (99.93% SiO2 and 0.05%Fe2O3) have been delineated. The Madhvani Group mined and used glass sands from Bukakata for making glass in the 1960’s. The area is currently submerged with little exposed beach.
At Katosi and Lwera for example, a cubic meter of sand costs 20,000 Uganda shillings, the workers on site are paid 50,000 Uganda shillings per day that they mine. Most of the active sand mines at Lwera are operated by the Chinese and the Elite Ugandan businessmen and religious leaders.
Stone Aggregate and Dimension Stones
Aggregates are a broad term that describes crushed stone, gravel, or sand used in the construction and building industry. Granite, gneiss, gabbro, dolerite, marble, basalt, quartzite, shale, marble, slate and sandstone are the most common rocks in Uganda that is being mined for aggregates and dimension stones by both ASMs and medium scale companies. The rocks have been crushed and used as aggregates, hard cores, rock fill, borrow pit sand, drainage channel, finishing and covers, man hall covers, and walk ways among others.
Uganda’s construction industry demand is growing at more than 6% per year and contributes 12% of Uganda’s GDP. The abundance and demand makes aggregate production a competitive business in the country for the local market. Dimension stone imports amounts to millions USD (despite in-country resources). Currently only DAO marble and Building Majesty Limited produce marble and granite slabs and other tile products respectively.
Uganda has several varieties of granite in abundant quantities in many locations throughout the whole country where it is quarried and supplied locally for construction purposes. The main granite quarries include Laroo and Kidere in Gulu District, Peta in Tororo District, Ochuloi in Soroto, Dokolo in Dokolo District, Akiya in Lira, and several localities in Mubende and Kiboga Districts.
Quartzites and slates are mined in several localities in the central region (Wakiso, Kampala, Lugazi, Mukono, Luwero etc) and in all the districts in the western and southwestern region overlain by metasedimentary sand, siltstone, and sandstone and quartzite ridges. The materials are supplied to support the construction industry in both the urban and the village areas. The slates are commonly used as decorative stones in houses and the dealers we interviewed in Eastern Uganda all stated that the suppliers are the same and trucks collect several varieties from different quarries. They are generally the mineral dealers who supply to local business men to market the products. The slate dealers in Kampala, Wakiso and Eastern Uganda all claim that the slates are quarried from Rakai and from the metasedimentary rocks on the Kibaran Fold Belt in western Uganda.
There are noticeable decline in food and cash crop production and education in the areas within the quarrying communities since all the elders, women, men, the youths and children all engage in quarrying to earn a living.
Marble and Limestone
Marble has been mined in Moroto, NE of Uganda by both ASMs and medium scale mining companies. Limestone on the other hand has been mined for cement and lime production in several places in Uganda (e.g. Moroto, Tororo Kinanira, Kigezi, Kisoro District, Muhokya, Kasese Dura, and in Kamwenge.
Over 300 million tons of pure white, smoky white and pink commercial marble deposits Marble exists in the Karamoja region, some of which are being exploited and transported to Tororo, Jinja and Mbale for cement manufacture and other construction products like slabs, tiles, terrazzo, aggregates, paint making, etc.
The main ASM mine sites include:
- Katikekile marble in Moroto District
- Moroto marble in Moroto district (extensive and variable in grades);
- Lokupoi and Moruangeber in Moroto district
- Forest Reserve marble;
- Toror Hill in Kotido district
- Naunyet, Ngolapulon and Nakagelmoru, Nakadapalait, in Kotido district
- Napak Hill in Napak district;
- Morumeri in Nakapiripirit District
Currently, there are companies that are mining or exploring for marble in the region that include; Tororo Cement Ltd, African Minerals Ltd, Great Lakes Ltd, Moroto Cement Industries (U) Ltd, Tiger Cement Ltd, Harambe African (U) Ltd, and Supercom International Ltd. Since 2012, Dao Marble Limited has been exploring and exploiting marble East of Moroto town from ML1291.
In Moroto, Marble is mined mostly by the ASMs using hoes, sticks and iron bars and crushing using hammers like any other stones described above. Currently, a 5 ton truck costs 80,000 Uganda shillings including loading. The cost also varies from season to season as explained by miners. During the rainy season, the market is scarce due to poor roads from the region to Mbale and therefore marble is sold cheaply unlike the dry seasons where demand is high.
Over 15,000 people are involved in marble mining; absolute poverty and climate variability over the past decade have sent natives into artisanal mining for the sub region mineral potential that has gold and marble. Marble involves breaking boulders into portable pieces as an additive to cement (Figure 28A). The stones are sold for cash to middle men, who transport them to Tororo Cement Industry. Despite the back aching activity income is meagre given the job done. However, the miners work under poor health conditions in all mining areas across the sub region.
Clay deposits suitable for the manufacture of bricks, tiles, pottery, etc. are widely distributed throughout Uganda. No detailed systematic investigation has been carried out throughout the country except around a few areas such as Kajjansi in Wakiso district; Bugungu near Jinja in Mukono district; Buteraniro in Mbarara district; Butende; Kasukengo in Masaka district; Malawa in Tororo district and Butema in Hoima district.
They are of variable quality, in terms of iron and quartz content and therefore show a highly variable reaction to firing. Careful and detailed investigation could show potential for better quality clays, including refractory material and china clay.
Clay in Uganda is a major raw material for various bricks and tiles in the building industry and pottery (Figure 30A and B). High aluminous clays with low iron content are used in making refractory bricks for lining furnaces, in making porcelain and in fine ceramics such as china ware (plates, cups), sanitary ware (toilet pans, basins, etc.) and pipes. Brick laying is till locally done in almost all villages in Uganda especially the swampy areas with the men mixing the mud and women mostly involved in ferrying water to the sites especially dry the dry seasons.
Brick making is one of the most serious threats to wetlands in Uganda today. This leaves behind big holes, which greatly hinder movement and communication. It is also associated with the clearing of vegetation around the wetlands so as to provide fuel with which to make them. Fires that are both natural and those started by man destroy the fertility of the wetlands. The fertility that had accumulated over the years in the soil is lost during the burning of the existing vegetation. These fires are caused by prolonged drought or clearing land for human activity.