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Category: Mufulira

Mufulira Mine Report

From Great North Road

By: Bridget Billany

An essay donated to the GNR by Bridget Billany, written in the mid-seventies as part of her HND.

Contents

Introduction

Plant area of Mufulira Mine at night.
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Plant area of Mufulira Mine at night.
Mufulira is situated in the Copperbelt of Zambia, and it is the largest underground copper mine in Africa. The Copperbelt is the most concentrated copper-producing area in the world, although fifty years ago it was wild and trackless. Now in an area thirty miles wide and seventy miles long there are eight producing mines, namely Mufulira, Rokana, Chingola, Bwana Mkubwa, Chambishi, Chibuluma, Konkola and Luanshya.

Mufulira has a population of 156,000 and is the fourth largest town in Zambia. The majority of the population is involved in the mining industry and the rest are concerned with trading, community services or smaller independent industries such as milling, engineering, timber and cement. However, although Mufulira is a thriving town with many shops and industries, none of these would have developed had it not been for the mine. Mufulira is her mine. It was the copper, which attracted people to settle down and set up business, and it is the copper, which keeps them there.

The mine is owned partly by the Zambian Government and partly by Roan Consolidated Copper Mines (RCM). As most of the population work on the mine RCM provides houses for its employees. They range from average two bedroom houses set in half an acre to big four or five bedroom houses set in a square acre. The mine also provides schools, although most of the employees' children go to boarding school in the United Kingdom or Rhodesia or South Africa. As well as houses the mine has built hospitals, clubs, and roads and it employs people such as plumbers, electricians, bricklayers, security guards and decorators to provide free services for the mine employees.

An aerial view of the town of Mufulira with the mine in the background.
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An aerial view of the town of Mufulira with the mine in the background.
Wages for a skilled worker, or a technical or professional man from overseas are extremely high and the standard of living of the country used to be really good. However over the years more and more Europeans have left as the economic situation of Zambia has deteriorated. It began with the white farmers leaving when the Government bought their farms and resold them to Africans, and then the Government bought private businesses from the Europeans and sold them to Africans. Now meat, vegetables and milk (basic commodities which were once plentiful and extremely cheap) are very rarely seen in shops and one has to pay very high prices for them when they are obtainable. The shops and supermarkets, which were once thriving businesses, are now usually empty and very badly run, and the cost of living is soaring. As I have already said the expatriates on the mine get very high wages and can afford this high cost of living but the average African in the street cannot and many of them turn to crime, robbing and stealing from the more wealthy members of the community. These conditions are driving more and more badly needed skilled and professional men away from Zambia, most expatriates now do one or perhaps two contracts (each one being for a two year period) where as at one time expatriates came out to work on the mines for one contract and ended up staying for ten. In the last five years even the old expatriates who may have been in the country for twenty to thirty years, have packed up and left.

However, for all the unwelcoming points now, Mufulira is still a very beautiful town and for those like myself who were born and brought up there leaving has not been an easy task. The weather is hot all year round, with a rainy season lasting from November to April, so most people lead a very social outdoor life of fishing, boating, riding, swimming, water-skiing, golfing or playing rugby, soccer, hockey or tennis.

An aerial view of Mufulira, showing the main shopping centre.
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An aerial view of Mufulira, showing the main shopping centre.
This introduction was intended to give a broad outline of the town of Mufulira and the life there, however the following chapters will be concerned with the development and running of Mufulira mine.

The Beginnings and Development

Evidence of copper was first discovered at Mufulira in 1923 by two prospectors named Moir and Bell. At that time there was no settlement there or within sixty miles, but, by 1951 a small town had formed along side a small concentrating plant, and now Mufulira is a large thriving town and her mine is the largest underground mine in Africa.

The creator of Northern Rhodesia (Zambia as it is now known) was Cecil John Rhodes. His ambition was not only to secure for Britain the mineral wealth of central Africa, but also to complete a rail route from the Cape to the Nile.

In London in 1889 Rhodes approached Lord Salisbury and offered to take for England the interior north of the Zambezi, and to finance its administration until the British public should awaken to the value of their new possession. Lord Salisbury accepted the offer and after further negotiations Rhodes and Lord Gifford (chairman of the Exploring Company and the Bechuanaland Exploration Company) formed an alliance and the British South Africa Company was formed. The object of this company was firstly to extend the railway and telegraph systems in the direction of the Zambezi; secondly to encourage emigration and colonization, thirdly to promote trade and commerce; and fourthly to develop and work mineral and other concessions under the management of one powerful organisation.

Map depicting copper-mining activities in Zambia.
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Map depicting copper-mining activities in Zambia.
In the next few years Rhodes concentrated on sending parties to make treaties with the tribes. The Government of North-Eastern Rhodesia was formally established by Order-in-Council in 1901, and Robert Codrington was the first administrator. Two years earlier in 1899 an Order-in-Council relating to Barotseland-North-Western Rhodesia had been signed under the administration of Robert Coryndon.

In the following ten years Codrington in the East and Coryndon in the West took the tasks to establish peace and the rule of law and to lay the foundations of a stable administration. Meanwhile the country was being opened up and the railway from Bulawayo reached Victoria Falls in 1904 (though Cecil Rhodes did not live to see it as he died in 1902); mining began at Broken Hill, which had been discovered in 1902; and as the railway crept northwards towns, farms and mission stations multiplied. The line reached Broken Hill in 1906, but it was not until 1909 that it was finally extended to link up with the 'Rhodesia-Katanga Junction Railway' on the Congo border.

The unification of Northern Rhodesia took place in 1911 with Mr. Wallace as Administrator and Livingstone was the Capital. It remained as such until Lusaka became the capital in 1954.

By 1911 there were fifteen hundred Europeans in the country and several mines were operating, and considerable farming had begun. The progress, which had been made in only eleven years, was a remarkable tribute to the pioneers and administrators.

Mufulira's history began in June 1925 when two prospectors named Moir and Bell were sent by Mr. Raymond Brooks, who was then in charge of all the prospecting for two major companies, to work up the west side of the Kafue River to the Congo Border and then come back down it again along the other bank. They found nothing on the way up but when coming back down they camped by a stream called the Mufulira, and there they found some peat moss stained with malachite. They sent some of this moss to Mr. Brooks and a short time later they discovered an outcrop, which also showed meager copper-carbonate stain. A sample of this was also sent to Brook, but unfortunately it did not amount to very much. Intact it was not until five years later in 1928 that this outcrop was more thoroughly investigated by geologists and the vast riches of Mufulira were revealed.

Towards the end of 1927 drilling programmes for Mufulira were approved by the board of the Selection Trust, and in March the first drill-hole showed a width of nearly twenty one feet of high-grade sulphide ore. Drilling proceeded continuously for two years and resulted in the development of one of the greatest copper mines in the world.

By November of 1950 a great deal of drilling and construction had been done on the basis of a potential treatment of 5.000 tons of ore a day, but the price of copper was dangerously low and it was decided to complete only one unit of the mill which was finished in December 1951- Meanwhile, the principal copper producers of the world had agreed to a drastic curtailment of production as from the beginning of January 1952, and so it was decided to defer bringing the mill into action. The mine was closed until July 1955 when a smelter was built on the property to help increase the plant's capacity of copper each year. The mine began operation in October 1955 and over 5.600 tons of copper was produced in the next nine months. Smelting started 5th January 1957, but the world copper restriction scheme continued until October, and was not until after that date that Mufulira was really able to get into its stride.

For the next fifteen years Mufulira continued to expand and develop and in November 1952 "the first tankhouse section of an electrolytic refinery was brought into operation, then in November 1955 a second section was commissioned. The refined copper casting plant began operations the following year, producing electrolytic wirebars and other shapes ready for sale to fabricators.

During 1956 and 1957, exploration by surface and underground drilling disclosed a western extension of the lower ore body and mining operations were increased by fifty per cent. The capacity of the milling and smelting- operations was also increased to handle the increased quantity of ore.

The third tankhouse of the refinery was commissioned in December 1965 and a further tankhouse in 1972. Monthly production capacity in 1974 was 21,000 tonnes of cathode copper per month, and the annual production was over 7,5 million tonnes of ore from which about 156,000 tonnes of copper was extracted.

Personnel joining the mining section of the mine from 1933 to the beginning of the 1960's went through every aspect of mining, whether they were unskilled or graduates. They would start as lashers working on the night shift at lashing the rock blasted on the day shift, and then taking it to the surface.

From lashing; they went to production tabulating and counting the amount of rock broken in a blast. Then they went into pipe fitting which involved installing pipes for water and air used for cooling machines and ventilation during drilling. After that they would go into timbering, which was building platforms for the rockbreakers, making ladderways, and ensuring that the passages underground were safe. Lastly they went to rockbreaking, which was laying explosives and blasting the rock. A rockbreaker had to break over 550 feet per month or he was taken off and put back to timbering. A top rockbreaker could mine around 1,200 feet of rock per month.

Administration structure on the Mufulira Mine.
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Administration structure on the Mufulira Mine.
Young men with mining degrees would start as learner mine officials and had to work right through from lasher to rockbreaker. However, nowadays graduates just work at the part of mining that they are specialized in, or they only learn one aspect of mining.

Before Independence in 1964, a European on the mine was known as a ganger or supervisor and was in charge of a gang of African labourers. Under him was an African 'boss boy', who was chosen from the labourers and given special training, since Independence and since the Zambian Government took over half of the mine, the Europeans have trained Africans to take on more responsible jobs and there are now African Shift Bosses, Mine Captains and future Managers.

The mine is divided into sections and each section is divided again, A Shift Boss oversees a small section and the gangs working there; the larger section is under the control of a Mine Captain; above a Mine Captain comes an Underground Manager, then a Superintendent manager, and finally the General Manager. All the different sections of the mine work very closely together as one section could not operate very efficiently on its own, and each one is equally important in the smooth running of the mine.

Production

There are many different methods of mining, but the main one used at Mufulira is 'open stoping'. There are several variations of this type of mining but basically it is the mining of huge sections of the ore body, leaving vast open caverns known as ore stopes. These open stopes may or may not be filled with waste rock or sand, depending on whether later caving is desirable. For example, if the stope is under a road or stream then it will be filled to prevent a cave in, however if it is under wasteland and caving will not affect production the stope is not filled.

Diagram of Mufulira Mine.
Enlarge
Diagram of Mufulira Mine.
Diagram of Mufulira Mine.
Enlarge
Diagram of Mufulira Mine.
The ore body strata are approximately 10 metres to 15 metres thick and lie in a plane at about a 45┬░degree angle to the horizontal. They are divided into blocks, on the mine surveyor and geologist charts, which can be as large as 100 metres long, 60 metres high and 40 metres wide, and each block is separated from the next by several metres of rock pillars.

Tunnels called crosscuts are mined into the blocks and then further tunnels known as drivers are driven horizontally through the blocks so linking the crosscuts. (see diagram). From these drivers, and at right angles to them, holes measuring about 4.5 cm diameter are drilled in 'fan rings' at intervals. These holes are later charges with blasting powder, and at one edge of the block a 2 to 3 metre section is mined out to leave an empty space called a 'slot'.

Further crosscuts are mined to the very base of the block and from these, inverted cone shaped excavations are made into the block and are called 'drawpoints'. The blasted rock falls down the slot into the draw points where it is later removed. The ground adjacent to the slot is then blasted and falls into the draw point. This process, called stoping, is repeated until the entire block is mined out.

The ore is removed from the draw points by front end loader caterpillars, which can carry three tons of ore at a time, and they tip the ore down ore passes which carry it to a common draw point on a lower level where it is control fed into rail cars which take it to an underground crushing station. The ore is crushed to a more manageable size of 15cm or less in diameter and then transported by conveyor belt to storage bins at the rock-hoisting shaft. Here it is fed into skips and hoisted to the surface.

Concentrator

Ball mills at Mufulira Mine.
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Ball mills at Mufulira Mine.
On the surface the ore is further crushed to less than 1 cm in diameter, and then it is placed in 'ball mills' which are large steel cylinders containing steel balls. These cylinders are rotated and after several hours of smashing and pounding within the mill, the ore is reduced to a fine dust, rather like face powder. Water is induced into the mill during this process so that the resulting product is a fine white paste.

The next step is flotation, where the paste is put into the tanks containing water and a special chemical and air is bubbled through this mixture. The chemicals cause rock particles containing copper to adhere to the air bubble and float to the surface, where it is scooped off. This concentration is about 46 percent copper. The waste collects as slime at the bottom of the tanks and is pumped out to a piece of wasteland known as a slimes dam.

Smelter

Converter aisle in the smelter at Mufulira Mine.
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Converter aisle in the smelter at Mufulira Mine.
Poler at Mufulira Mine.
Enlarge
Poler at Mufulira Mine.
The concentrate is mixed with limestone to act as a flux and then it is smelted in a reverberatory furnace. This smelting forms waste slag, which floats to the surface and copper and iron sulphides, known as 'matte', sink to the bottom where they are drawn off and placed in a 'converter' furnace.

Here high-pressure air is blown through the sulphides and the iron sulphides are oxidised to iron oxide, and then a siliceous flux is added which reacts with the iron oxide to form a floating slag, which is then skimmed off.

Next the copper sulphides are oxidised to form metallic copper known as 'blister' copper. The sulphur is oxidised as well and given off as sulphur dioxide gas -- the pungent fumes always associated with a copper smelter. The blister copper is then conveyed to the anode furnace where it is further oxidised to remove any remaining traces of sulphur.

Next it is 'poled' to remove excess oxygen. Poling is a process where green hardwood tree trunks are forced into molten copper. The oxygen in the copper literally burns with the wood, forming carbon dioxide gas, which is given off. The ash floats as slag and is skimmed off.

The copper is now 99.8 per cent pure, but for modern industry this is not pure enough, so from the anode furnace the copper is cast into anodes, (so called because they will form the anode in the electrolytic refining process).

Refinery

Wirebar casting in the refinery at Mufulira Mine.
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Wirebar casting in the refinery at Mufulira Mine.
Mufulira Mine tankhouse.
Enlarge
Mufulira Mine tankhouse.
In the refinery tankhouse anodes are packed alternately with thin pure copper starting sheets, called cathodes. They are packed closely but not touching, and are wired to a direct electric current with the anodes being positive and the cathodes negative.

They are immersed in a tank containing sulphuric acid solution, which acts as the electrolyte. Through electrolysis, the ions of pure copper are displaced from the anodes and reform on the cathodes. Any impurities or contaminated metal settles at the bottom of the tank as sludge as the anode dissolves.

The sludge contains minute amounts of minerals such as bismuth, gold, silver uranium and platinum. These are removed and processed as they account for a valuable proportion of Zambia's exports.

The cathodes are now 99.97 per cent pure copper and they are melted down in furnaces and cast into wire bars. These bars are then ready for export to countries all over the world.

The Importance of the Mine

The whole of Mufulira's economy relies on the mine and life there evolves completely around it. Of her 156,000 population, about 15% are mine employees and the rest depend totally on the mine for their livelihood. For instance all the people who work in the town in shops and offices would not have jobs if it wasn't for the mine, and the factories and industries which employ thousands of people would not exist if the mine wasn't there. In short, if the mine was to shut down the town would die because the European mine employees would leave and the Africans would be unemployed, all the associated industries would have to close causing great unemployment, and workers would leave the town to look else where for jobs. If the majority of the population left then all the trading area of the town would also be forced to close and soon Mufulira would be no more than a memory.

The people of Mufulira realise how important the mine is and that's why seven years ago when disaster struck and threatened to close the mine, the whole population fought night and day to keep the mine open.

The accident happened in the early morning of 25 September 1970, when half of the mine was flooded and eighty-nine men were killed. Total production was reduced to one fifteenth of normal and a great battle began to save the mine from complete devastation.

Diagram depicting the inrush of the Mufilira Mine disaster.
Enlarge
Diagram depicting the inrush of the Mufilira Mine disaster.
The accident was caused because mud and water from the 'slimes dam' had seeped through cracks in an over hanging wall in an old slope and eventually the force of the mud and the pressure of the slimes dam caused a section of the over hanging wall to give way, and the mud and water rushed into the Eastern section of the mine and flooded all shafts below 500 metres. Fortunately the pump station on the 500-metre level was saved and prevented the rest of the mine being flooded.

The slimes dam is made up of powder waste from the concentrator. After the copper and waste have been separated in the concentrator, the waste is mixed with water and pumped out into a large area of wasteland. Over the years a small lake of mud forms and this is how it gets the name slimes dam. The actual slimes dam that flooded the mine was situated on top of a disused part of the mine, and waste had not been pumped there for some years, (it was, and still is, pumped to an area far away from the mine). The stope below the dam was mined out but had not been filled, so it was like an empty cavern, and mud seeped through cracks in the surface. Although mud and bits of tree had been found under ground the day before the disaster, there was no time for investigations to begin because the hanging wall gave way and sludge and mud poured into the mine with a pressure of more than 1,000 lbs per square inch.

The men working in the shafts below 500 metres stood no chance of escaping, most of them were killed by the force of the mud before they had time to drown. Men on higher shafts, on realising what had happened, desperately scrambled to the cages to get to the surface. It was only when these first few survivors reached the surface that the full extent of the disaster was realised.

Eighty-nine men were killed and if the disaster had happened six hours later hundreds, if not a thousand, would have been killed. Rescue operations began immediately and from mid-morning of Friday 25 September fifty sorties were carried out by mine rescue teams from all the Copperbelt mines. The teams exposed themselves to extreme danger, as there could be no guarantee that a further inrush of mud would not occur. They examined every accessible section of the affected part of the mine and rescued four men who would otherwise have died. However, by the 30th September it was decided that there was no hope of further survivors and the rescue teams were withdrawn.

If ever a mine was well served by its engineers, Mufulira was. Early on they had decided on the site for an emergency pumping system as water was rising in the shaft at eight inches per minute and a whole range of decisions had to be made quickly and accurately as to where the water was to be held and then relayed to the 454 metre pump station. As an additional precaution and to guard against failure to hold the rising water, massive concrete bulkheads were built west of the emergency pumping to protect the undamaged end of the mine.

Consultants were flown in to advise on how to improve the overall situation by working on the slimes dam from which the mud had flowed into the mine. A huge sinkhole had formed in the slimes dam and the essential work of preventing further flooding had to be completed before the end of November when the seasonal rains began. So drains were made to carry rainwater away from the sinkhole, and free water lying in the base of the sinkhole was pumped away.

Work to clear the mine continued twenty-four hours per day for the following months. There were many accidents, which set back the operations, and the maintenance of the morale of the workers was almost as important as the mine itself. The effect of the disaster on the small community of Mufulira was profound and although there was no problem for the first few days because of pressure of events, it was realised that there would be a considerable reaction when this period ended. To keep up morale all available information was passed on to employees, and in spite of the very heavy pressure on scarce engineering resources, a full-scale planning exercise was initiated aimed at restoring the mine to full capacity. Knowledge of this helped to reassure employees that their own future was secure and that management had every confidence that all the problems would, eventually, be overcome.

As soon as the urgent work of securing the surface was substantially completed a range of investigation was carried out on the slimes dam and any risk of a similar disaster was looked at and ruled out. Gradually production picked up as parts of the flooded shaft were cleared and worked. By 1974 the mine was back to full production although parts of the flooded mine are still now, six and a half years later, being cleared of mud and there are parts which are not going to be cleared as it is thought to be uneconomical to do so.

This disaster very nearly closed one of the most important underground mines in the world and if this had have happened it would have cost millions, if not billions of pounds to re-open and re-build, and if it had not been reopened there would have been hundreds of millions of tonnes of untapped copper left underground.

The devastation of Mufulira mine would have been a major blow to Zambia's economy, but thanks to the determination, skill, and hard work of the population, Mufulira is back to normal production and is now concentrating on improving production.

Conclusion

Zambia relies very heavily on her copper exports and her economy has suffered greatly due to the falling price of copper on the world market over the past few years. In April 1974, copper prices were at 150 US cents a pound (that is pound in weight). But by October of the same year prices fell to 62 US cents a pound. The principal determination of copper prices in the short-term is the level of industrial production, particularly in the electrical industry, which consumes almost half of the world's supply of copper.

However, many other factors are important, notably the level of stocks and expected changes in demand. Prices are now at about 80 US cents a pound.

Production has had to be cut back considerably because of the falling copper prices, but still many thousands of people on the Copperbelt rely on the mining industry for their livelihood. So if a major mine like Mufulira had to be shut down because of a disaster similar to the one in 1970 or if ore deposits ran out, all these people would loose their jobs and Zambia's economy would suffer a severe blow. In 1974 Zambia exported 687,000 tonnes of copper to countries all over the world, including the United Kingdom, West Germany and Japan. This amounted to more than K686, 500 thousand and accounted for 94 per cent of the countries export earnings.

Estimated ore reserves at 50 June 1974 were 140,697,000 tonnes at 3.22 per cent copper, so although there are still perhaps twenty five years of mining left at Mufulira, the copper will have to run out at some time and then what will become of the town?

One can only speculate as to the future of Mufulira, but at present should the mine cease to function the town would rapidly die. Thus unless her economy is diversified into industry and agriculture, I doubt the town of Mufulira will outlive the mine by more than two years.

Bibliography

Copper Venture by R. Kenneth.
An Outline of Mining Operations at Mufulira by D. Young
How Mufulira has been Rehabilitated by R. Neller, J. Sandy and V. Oliver
Zambian Mining Year Book 1974
Mufulira Division Annual Publication 1974
Lloyds Bank Ltd Economic Reports of 1973 and 1974

And my special thanks to Mr. Banda of the Zambian Appointments Division of Roan Consolidated Mines Ltd., and Mr. N. P. Billany for all the invaluable help that they gave me with this essay.

Retrieved from "http://www.greatnorthroad.org/boma/Mufulira_Mine_Report"

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