MINERAL POTENTIAL OF MALAWI
OPPORTUNITIES FOR MINERAL INVESTMENT
GRAIN W.P. MALUNGA MIMM
P.O. BOX 566 JUNE 2001
BLANTYRE
MALAWI
TABLE OF CONTENTS
INTRODUCTION 3
1.0 BAUXITE 3
2.0 HIGH CALCIUM MARBLE 4
3.0 MONAZITE AND STRONTIANITE 5
4.0 TITANIUM 5
5.0 PHOSPHATE 6
6.0 PYROCHLORE 6
7.0 URANIUM 6
8.0 VERMICULITE 6
9.0 COAL 7
10.0 CLAY 7
11.0 GEMSTONES 8
12.0 GRAPHITE 8
13.0 GLASS SANDS 8
14.0 GEOCHEMICAL ANOMALIES 9
15.0 GEOPHYSICAL ANOMALIES 10
16.0 INCENTIVES FOR THE MINING SECTOR 11
17.0 KEY ORGANISATIONS 12
FIGURES
MINERAL RESOURCES OF MALAWI
INTERNATIONAL TRADE ROUTES
MINERAL POTENTIAL OF MALAWI
INTRODUCTION
Agriculture has been dominating the economy of the country employing about 80% of the labour force and accounting for almost 90% of the export earnings. The uncertainty of the weather and recent drought have, however, shown the risk of relying on agricultural output alone.
The Malawi Government is now convinced that our ability to diversify and turn around the economy lies in mounting an aggressive promotional campaign to attract both local and international investors to establish a viable mining industry by exploring and exploiting known mineral deposits.
To support this, Government established the necessary institutional set-up and an attractive legal framework that defines the investor's rights and obligations. Security of tenure is guaranteed to give maximum security to the investor. This is strengthened further through Malawi's membership in Multilateral Investment Guarantee Agency (MIGA) and in International Centre for the Settlement of Investment Disputes (ICSID).
This document outlines the mineral potential of the country and the available incentives for the Mining Sector. It will be noted that more information regarding the mining sector in Malawi and the available incentives can be obtained from key organisations listed at the end of the document.
1.0 BAUXITE
The bauxite deposits on Mulanje mountain are at an elevation of between 1800 and 2000 metres. The deposits are accessible through foot paths. The nearest rail is Luchenza which is some 30 kilometres from the deposits. Luchenza is about 38 kilometres from Blantyre.
Work on two deposits, Lichenya and Linje, has estimated the existence of 28.8 million tonnes within an average depth of 4.5 metres. Total reserves on the mountain are estimated to be in excess of 50 million tonnes.
The average analysis of the deposit is:-
Al2O3 / Free quartz / Combined silica / Fe2O3 / TiO2 / Kaolinite / LIO43.3 / 13.3 / 2.2 / 14.2 / 1.8 / <5.0 / 28.8
The bauxite is mainly a trihydrate gibbsite which lies over kaolinite and has free quartz and geothite as the main contaminants.
Feasibility study executed by MIDCOR through a consultant, MET-CHEM Canada Inc., proposed a mining output of 580, 000 tonnes of bauxite per annum to produce 200,000 tonnes of alumina to meet an annual production of 100,000 tonnes of aluminium.
The bauxite will be beneficiated to reduce the quartz content before processing it using the Bayer process. The Alcan P-180 cell will be used for aluminium smelting. The study was conducted in such a manner as to allow the development of Mulanje bauxite in phases of bauxite mining (US$ 25.6 million), alumina (US$ 205.5 million) and aluminium (591 million). This means that the total capital costs for the whole project will be in the region of US$ 822 million. Power exists locally for mining and production of alumina while the production of aluminium will currently depend on the availability of power from Cabora Bassa which will be in the region of 15.3 kWh per Kg of aluminium produced.
A market for alumina will be Richards Bay in South Africa. The world demand for aluminium consumption has been projected to grow at a rate of 2% per annum. Should aluminium be produced it will find its way to the world market through London Metal Exchange.
Increased interests on the deposit continue to be expressed.
2.0 HIGH CALCIUM MARBLE
There exist a high calcium marble deposit on Malowa hill east of Golomoti in the Bwanje Valley. The marble lies on basement gneiss and granulitic rocks and has been intruded by quartz feldspathic rocks having a granitic affinity.
A total of 4.08 million tonnes have been proved for the manufacture of chemical grade lime. The reserve contains an average grade of 52.% CaO, 0.99% MgO and 5.22% SiO2. A probable reserve of 14.85 million tonnes containing 46.83% CaO and 1.36 MgO has been delineated for the calcitic marble unit.
There exist also dolomitic marble amounting to a proved reserve of 3.7 million tonnes. This unit contains an average of 36.21% CaO, 12.99% MgO, and 8.6% SiO2. A probable reserve of 17.53 million tonnes has been estimated to contain 36.61% CaO, 7.14% MgO. This tonnage also includes impure marbles.
The overall resource estimate for Malowa marble is therefore 22.38 million tonnes with a combined proved reserve of 7.78 million tonnes.
The Bwanje Valley limestone project aims at establishing lime works at Malowa. The main products to be manufactured will be high quality hydrated lime and pulverised limestone.
A plant has been designed to produce 50 tonnes per day of quick lime (equivalent to 60 tonnes per day of hydrated lime). This capacity has been based from the current demand of lime and should any increase in demand be noticed then a duplicate unit will be installed.
About 20 tonnes of pulverised limestone will be produced per day while 30 tonnes of agriculture limestone will be produced per day.
Before calcination, the run of mine will go through a primary crusher with a capacity of 40 tonnes per hour in order to reduce it to less than 75 mm. After primary crushing the material will go through a secondary crushing unit to produce feed size for the kiln and agriculture limestone product,
Malowa marble is fine to coarse grained and decrepitates on calcination. This marble characteristic can be accommodated in a fluid bed kiln (Fluo-Solids) kiln being manufactured by Dorr-Oliver. This type of kiln is already operational on a similar deposit in the United States.
After calcination, the quick lime will be hydrated to produce hydrated lime having 85% passing through a 200 mesh (75 micron)
This project will utilise coal as fuel for the kiln.
The capital cost estimate for the whole project is US$ 10.8 million. This includes capital costs for mine, crushing, calcination and hydration.
There is a local demand for lime of 15,000 tonnes per annum especially in the agro-processing industries particularly in sugar, tobacco, fertiliser and chemical manufacture. There is also an export market potential for Zimbabwe, Mozambique and South Africa.
3.0 MONAZITE AND STRONTIANITE
A high cerium and low thorium pistachio-green monazite and strontianite carbonatite exists on Kangankunde hill along Lilongwe -Blantyre (Zalewa) road in Southern Malawi. The mineral occurs in association with florencite, bastnaesite, manganese oxides, sphalerite, barite and apatite. The ore body consists of spotted dark and light coloured carbonatite and dark brown to black porous ankeritic carbonatite.
Latest prospecting results by BRGM of France on the grade and amenability to ore processing showed that there are 2 million tonnes of possible reserves at 6.6% monazite and 546,000 tonnes of minable reserves averaging 10.3% monazite. Drill indicated reserves amount to 11 million tonnes of ore having 2.0% rare earth oxides and 8% strontianite
Pilot processing tests by gravity and magnetic separation gave an 81% monazite concentrate with a recovery of 80%.
A feasibility study is required to establish technical and economic viability of the project.
COMPOSITION OF KANGANKUNDE MONAZITE IN RELATION TO WEST AUSTRALIAN SANDS AND TITANIUM
REO / KANGANKUNDEMONAZITES / WEST AUSTRALIAN MONAZITES (SANDS)
La2O3 / 30.41 / 24.59
Ce2O3 / 50.93 / 45.50
Pr6O11 / 4.5 / 5.02
Nd2O3 / 13.21 / 16.53
Sm2O3 / 1.43 / 2.52
Eu2O3 / 0.17 / 0.03
Gd2O3 / 0.49 / 1.76
Tb4O7 / - / -
Dy2O3 / 0.16 / 0.95
Ho2O3 / - / 0.05
Tm2O3 / - / 0.05
Er2O3 / 0.06 / 0.45
Yb2O3 / 0.03 / 0.12
Lu2O3 / - / 0.02
Y2O3 / 0.10 / 2.38
TOTAL / 66.70 / 59.78
Strontianite can be recovered as a by-product in the concentration of monazite. It has been established that the ore bodies contain 10% to 70% of strontianite and that it extends beyond the limit of monazite mineralisation.
4.0 TITANIUM
Beach sands with high heavy mineral content exist over long stretches of the lake in Salima and along the eastern lake shore. The sands contain ilmenite, rutile, monazite and zircon. A mining company carried out some work in part of the area and delineated about 670,000 tones of heavy mineral concentrate. The delineated area can be worked by a dredge.
Very large tonnage estimated to be in the region of 100 million tonnes exist as colluvial sand and gravel near a rail line at Tengani. Heavy mineral content ranges from 3.5 to 35%. The rutile : ilmenite ratio in the heavy mineral fractions ranges from 12:1 to 4:1. Recent exploration work by the Geological Survey Department indicated 2.5 million tonnes of sand containing 3% ilmenite and 300,000 tonnes of sand containing 0.3% rutile.
5.0 PHOSPHATE
Carbonatite phosphate deposits occur at Thundulu in form of apatite carbonatite, apatite sovite and apatite carbonatite.
Drill indicated reserves amount to 1.9 million tonnes within a depth of 50 metres. The rock contains between 15% and 20% P2O5 and is suitable for the manufacture of phosphatic fertiliser.
6.0 PYROCHLORE
The most promising niobium prospects in Malawi are at Ilomba hill, Chilwa Island and Thundulu. The pyrochlore at Ilomba occurs in pyroxenite lenticles in aegerine foyaite associated with a syenitic ring complex. Inferred reserves stand at 100 thousand tonnes at 3% Nb2O5.
Pyrochlore rich carbonatite occurs at Chilwa Island. Reserves have been put at 375 thousand tonnes containing 0.95% Nb2O5. Geological reserves are believed to be substantial.
Thundulu carbonatite hosts reserves estimated at 900 thousand tonnes containing 0.37% Nb2O5.
7.0 URANIUM
Uranium mineralisation occurs in Karroo sandstone at Kayerekera in the North Rukuru Basin. Detailed evaluation has revealed some reserves estimated at 10 thousand tonnes at 0.17% uranium. Development of the deposit will depend on behaviour of prices on the world market.
8.0 VERMICULITE
15 deposits were identified around Feremu in Mwanza. A pitting and drilling excercise delineated reserves amounting to 2.5 million tonnes. The vermiculite forms a core surrounded by hydrobiotite and phlogopite. An expansion ratio of greater than 10 was observed on vermiculite from Garafa, Phate, Matembe north and south, Kapirikamodzi and Njiza.
9.0 COAL
There are five identified coal fields with estimated reserves of 20 million tonnes and about 750 million tonnes of probable reserves. Exploration results have shown that :-
(i) Ngana coal field hosts coal with an average of 21 % ash content and with a calorific value of 4799 KCal/Kg
(ii) North Rukuru - Nthalire coal field has an average coal ash content of 28 % and a calorific value of 5410 KCal/Kg
(iii) Livingstonia coal field coal contains an average ash content of 14 % and a calorific value of 7226 KCal/Kg
(iv) The coal in Lengwe coal field has an average ash content of 50 % with a calorific value of 4250 KCal/Kg and
(v) Mwabvi coal field hosts coal with an average ash content of 40 % and a calorific value of 5030 KCal/Kg
All these coal fields have less than 8 % sulphur content. Estimated reserves show that there are :-
- 15 million tonnes of coal at Ngana in Karonga
- 2 million tonnes at (Mchenga), Livingstonia, in Rumphi and
- 4 million tonnes at Mwabvi in Nsanje
Vwaza and Chirumba basins are potential coal fields but no reconnaissance
drilling has been undertaken.
The main consumers of coal are in cement manufacturing, textile and soap making. There is more potential for use of coal in the tea industry, tobacco industry and thermal power generation. There is also room for domestic application through the use of coal briquettes.
10 CLAY
1 Linthipe clay
This clay covers an area of 7.6 kilometres. The clay has a density of 1.86 t/m3 and an estimated reserve of 14.1 million tonnes. The clay is a weathering product of an anorthosite body. It has a higher firing shrinkage of 5-13 % and therefore requires addition of silica sand and feldspar fillers to a proportion of 25 % for each to reduce the shrinkage to 1.8 %.
The clay has the following chemical composition:
SiO2 46.7 %
Al2O3 33.8 %
Fe2O3 2.0 %
CaO 1.1 %
MgO 0.26
K2O+Na2O 0.28
2 Bangwe East Clays
This resource is suitable for brick making. The area is between Bangwe and Nguludi mountains near Blantyre. These soils cover about 40 km2. The soils are derived from weathering of the underlying perthite gneisses and perthosites. He estimated that about 17,500 million bricks could be produced by traditional methods and about 26,500 million bricks could be made by mechanised brick plants. These bricks can be produced in those areas that contain about 50 % silt and clay.
11.0 GEMSTONES
Precious and semi precious stones have being mined by small scale miners in 14 of Malawi's 24 districts. Among these are aquamarine, amethyst and rhodolite. It is estimated that between 1,000 grams and 5,000 grams of fine grade stones are being mined every month. The stones are mostly found in pegmatites. The main producing districts are Mzimba, Rumphi, Chitipa, Ntcheu and Nsanje.