The piece “Strategic Minerals for a Developing Economy” featured below was initially published in Malawi’s Mining Review Issue Number 28 2015 that is circulating this August 2015.
The full edition is available for download here. This monthly publication is edited by Marcel Chimwala.
Ever thought of how simple life is with commodities that surround us? Ever noticed that life is supported by electricity, metallic materials, cement products and glass? Without coal, iron ore, limestone and glass sand we would not enjoy luxurious life of cars, living in apartments, seeing through our closed windows and crossing rivers through bridges. Every country should strive to look at these four minerals/commodities as a basis for economic development and of strategic importance.
Coal, iron ore, limestone and glass sand are bulky low value minerals; but of strategic importance for any country to develop its primary industry and infrastructure. Coal is required for electricity generation and steel production from iron ore. A country needs steel for infrastructure development such as bridges and high rise buildings. Limestone is essential in cement production which is required in buildings, bridges and other infrastructure products. Glass sand or silica dioxide is needed in manufacture of glass be it for windows, wind screens and containers.
These are building blocks for the economy and nations should strive to encourage its citizens to develop these mineral resources through economic empowerment or state owned enterprises that strategically look into import substitution and regional exports.
STRATEGIC MINERALS FOR A DEVELOPING ECONOMY
Coal is one of the three most important fossil fuels that include oil and gas. Coal is formed from accumulation of plants in a non-oxidizing marine environment. This type of environment prevents plants from decay and their continued burying by mud and sand compacts them for a long period forming coal. 10 metre layer of compacted plants forms 1 metre seam of coal.
The main use of coal is for electricity generation and in Malawi it is mainly used for generating steam that is required in agro-processing such as tobacco, tea and textile manufacturing. Ethanol and fertilizer manufacturing also uses coal for heating their boilers. High grade coal is used in the manufacture of coke for use in the steel industry.During thermal power generation, coal residues such as gases, tars and others can be captured and used in a number of manufacturing processes. Plastics, roofing, linoleum, synthetic rubber, insecticides, paint products, medicines, solvents and synthetic fibers can come from coal-derived compounds.Coal can also be used as a household fuel in form of briquettes.
Heat and pressure transforms coal into various stages of composition and properties. The whole process turns coal from peat (carbon content of less than 60%) to anthracite (carbon content of over 87%) through lignite (carbon content of 60 – 70%), sub-bituminous (carbon content of 71 – 77%) and bituminous (carbon content of 77 – 87%). Malawi coal is sub-bituminous to bituminous and is found in the Lower Shire Valley and northern region.
Coal in the north has been found in Livingstonia, Nthalire, North Rukuru and Ngana basins while in the south it has been found in the Lengwe and Mwabvi basins. Coal in Malawi has been observed in the rocks of the Lower Karroo age commonly known as the K2 beds. These beds are usually characterised by conglomerates, sandstones, shales and mudstones with carbonaceous shales and the coal itself.
Vwaza basin has the possibility of hosting coal.
Iron ore is a source of metallic iron or pig iron which is integral to the global economy. Its main source is magnetite (Fe3O4) and hematite (Fe2O3) which when they constitutes greater than 60% iron form natural ore. Iron ore can vary in colour from dark grey, bright yellow, deep purple, to rusty red.
Mindale Hill deposit outcrops for about 300 metres within a width of 15 metres. The deposit is magnetite interbedded with granular apatite. Three or four thinner bands dip at 700 to the west. The ore requires crushing and magnetic separation to recover the two minerals.
A band of iron ore,in the form of specular hematite, is found near Dzonze Mountain, along Mtendere, in Ntcheu district. Magnetic survey reveals that the deposit may be wider and spanning to several kilometers. Other smaller pockets or bands have been noticed in pegmatite bands and carbonatites such as specular hematite at Tundulu.
The main constraint of mining iron ore economically is its position relative to market, the cost of rail infrastructure to get it to market and the energy cost to beneficiate and turn it into pig iron or steel. This is a high volume but low value business and yet crucial to modern life of structural engineering applications, maritime purposes, automobiles, and production of various types of machines.
Limestone in Malawi is dominated by marble bands in metamorphic rocks of central and southern Malawi while sedimentary limestones are common in the northern region. Other limestone resources that have potential to be extracted are carbonatites at Chilwa and Tundulucrabonatites in Zomba and Phalombe respectively. The most important resources are at Njereza in Mangochi, Chenkumbi in Balaka, Chikoa-Livwezi in Kasungu and Malowa in Ntcheu. Here high calcium and low magnesia limestone has been delineated (Table 1).
Limestone will continue to be the most important mineral resource in the absence of uranium production at Kayerekera. The emergence of Shayona Cement Corporation and Cement Products Limited has increased exploitation of limestone for cement production. Limestone for soil conditioning is being undertaken around Matope area and Chenkumbi.
Sedimentary limestones have been observed in Karonga at Chiweta, Uliwa, Mwesia and Ngana. These are associated with Chiwondo beds made up of mudstone and shaley sequences. They occur as marl stone or nodular limestone.
Glass sand is commonly known as silica sand because it is almost entirely composed of silica dioxide and contains minute impurities of iron (Fe2O3), aluminium oxide (Al2O3), calcium oxide (CaO) and magnesium oxide (MgO). This is typical of Mchinji dambo sand (Table 1). Heating sand to about 17000C melts it into a liquid that turns into glass after cooling. When glass is molten it is easy to shape and when it is set into various shapes such as flat sheet (for windows) and glass containers (e.g. bottles or tumblers), it becomes chemically inert so as not to react with any chemical and it can be recycled many times. The glass that we use is a product of sand, soda ash (NaCO3), and limestone (CaCO3) to make sodium-lime-silica glass that we see around us. Soda ash reduces the temperature at which sand melts while limestone makes the glass not to dissolve in water.
Glass can assume different appearances through addition of chemicals and metals. Addition of iron and chrome will make glass tinted green while addition of metals make glass look stained. Addition of boron oxide makes glass tougher to be used in microwaves. PYREX® is a good example of glass added with boron oxide.
Table 1: Chemical characteristics of glass sand
|% CaO + MgO
|Flint Containers and Table Ware||95.0 – 98.5||98.2||0.04||0.5 – 4.0||0.28||0.2 – 0.5||0.28|
|Sheet and Plate Glass||95.0 – 98.5||98.2||0.06||0.5 – 4.0||0.28||0.5||0.28|
|Green Glass||95.0 – 98.0||98.2||0.3||0.5 -4.0||0.28||0.5||0.28|
|Amber Glass||95.0 – 98.0||98.2||1.0||0.42||0.5 – 4.0||0.28||0.5||0.28|
MINERAL RESOURCE DEVELOPMENT AND CONSTRAINTS
Table 2 shows the level of knowledge on quantity of minerals in demarcated areas. This only indicates the reserves in specific areas where work was done. The classification of tonnage from inferred to measured resources is a factor of level of certainty where “inferred” gives less confidence and “measured” gives more confidence that the mineral is there and a feasibility study can be undertaken to determine whether mining can take place at profit.
Table 2: Strategic commodities for economic development in Malawi
|Ngana||15||50||30.2% ash, 2.2% S and 4708 Kcal/kg||Feasibility|
|North Rukuru||5||150||32.4% ash, 0.6% S and 4781 Kcal/kg||Follow-up|
|Livingstonia||1.4||5||20||17% ash, 0.5% S and 6800 Kcal/kg||Pre-feasibility|
|Lengwe||10||59.2% ash, 0.51% S and 2746 Kcal/kg||Follow-up|
|Mwabvi||5||10||40% ash, 0.76% S and 4173 Kcal/kg||Pre-feasibility|
|Mchenga||1.4||5||14% ash, 4799Kcal/kg||Feasibility|
|Iron ore||Mindale||0.5||3.3||67.5 Fe||Pre-feasibility|
|Uliwa and Mwesia sedimentary limestones||709,629||42% Ca0, 15% SiO2||Pre-feasibility|
|Njereza||98.0||53.0 CaO, 2.0% Mg0||Feasibility|
|Chikowa/Livwezi||10||Approximately 17 Mt of cement grade, 51.0% CaO, 0.7% MgO||Feasibility|
|Chenkumbi||20||300||46.1% CaO, 6.3% MgO||Feasibility|
|Malowa||14.0||3||53.6% CaO, 1.4% MgO||Feasibility|
|Chilwa Island||52.1% CaO, 0.2% MgO (grab sample)||Pre-feasibility|
|Tundulu Hill||50.9% CaO, 0.8% MgO (grab sample)||Pre-feasibility|
|Songwe Hill||46.5% CaO, 0.6% MgO (grab sample)||Follow-up|
|Glass Sands||Mchinji: Chimwang’ombe, Chitapalume, Tsumba, Kachusi-Thumba, Nabiumi, Elenesto||1.6||97% SiO2&< 0.2% Fe2O3||Pre-feasibility|
|Lake Chilwa Sand Bar||25.0||92.7, 0.62 Fe2O3||Pre-feasibility|
As previously indicated, these minerals play a crucial role in indicating the level of economic development of a country. The buildings, tarmac roads, steel towers, motor vehicles and bridges have components of these minerals. Government will serve a lot of FOREX if it makes a drive to develop them for import substitution.
The problems that are hindering mineral resources development in Malawi include a weak economy that is failing to support the mining sector due to high capital requirement for setting up mining ventures, lack of a state owned mining company that can develop strategic minerals to support local industry and promote economic empowerment to local Malawians, poor funding and lack of adequate human resources in public institutions to undertake strategic mineral resource development. All these are compounded with unfair extreme expectations on the contribution of mining to community engagement and social development.
Two initiatives can be undertaken to fund such projects. One is to speed up the establishment of a Development Finance Institution to fund strategic economic ventures such strategic minerals and agro processing facilities for value addition in order to boost exports and self-sufficiency. Malawi Savings Bank would have been an appropriate vehicle for easy set-up. The second initiative would be to re-establish Mining Investment and Development Corporation (MIDCOR).
Unfortunately, MIDCOR was heavily politicized and fell victim to the so call “Structural Adjustment Program” which in Malawi was not well thought off and led us to economic misery that we see now. The idea of having MIDCOR was to promote and speed up the development of the mineral sector. All mature projects were to undergo divesture to Malawians as an initiative of creating a middle to upper class Malawian employers and to reduce capital flight by global companies due to various reasons such as global financial crisis and political insecurity.
Malawi’s economic policies need to be redefined if the country can move forward in promoting economic independence. Institutions of higher learning should now focus on minerals and industrial education producing quality technicians and graduates that are relevant with the needs of the industries and Malawi’s economic development path. Universities should develop relevant curriculum that will fit in with the growing financial and economic needs of the nation.
- Bloomfield, K. and Garson, M. S. 1965. The geology of the Kirk Range-Lisungwe Valley area. Bull. Geol. Surv. Malawi, 17.
- Malunga, G. W. P. 1996. Coal in Malawi. Unpublished Report
- Malunga, G. W. P. 1996. Limestone Resources for Production of cement in Malawi. Unpublished Report
- Malunga, G. W. P. 1997. Mineral Potential of Malawi. Unpublished Report.
- Malunga,G.W. P. 2014. An analysis of the Mineral Resources of Malawi, ISBN 978-99908-950-01
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