Mines,Mining and Exploration in Africa

The venue: The J.C. Lemmer Auditorium at the SA National Museum of Military History

Central Rand Gold (CRG), South Africa’s newest gold mining company is planning to reopen old worked out areas on the Central Witwatersrand where 120 years ago the largest and richest deposit of gold was discovered.

It is estimated that there are still millions of ounces of gold to be gained from the very site where gold was mined following the discovery of the Witwatersrand Goldfield.

How can one be sure that there are so much gold to be won and how is it going to be possible to determine precisely where the best places are to start operations?

One man, the author of The Golden Crown of Johannesburg, Gerhard von Ketelhodt, knows the answer. Von Ketelhodt, who was the last mine overseer at Crown Mines to work in the area about to be opened, knows where the millions of ounces of gold to be mined are located.

The ‘Golden Crown’ was Crown Mines, in its heyday the world’s greatest and richest mine. That old mine was the lifeblood of Johannesburg, a city which grew from a mining camp into a great metropolis in just a few decades. In his book, a new release, the author relates how Crown Mines was established, its heyday, its decline and its hard fought battle for survival.

How Gerhard Freiherr von Ketelhodt, a man of noble rank, a Baron from Germany, came to join Crown Mines in 1956 is part of an incredibly fascinating story. Von Ketelhodt emigrated to South Africa from Germany to manage a farm in the Eastern Cape, but having qualified as a coalminer in the Ruhr district in Germany subsequently joined Crown Mines as a learner miner in 1956. He describes his life and experiences on the mine and how he had to overcome not only the difficulties and hardships inherent in the job but also the problems of communication when he arrived without a knowledge of English, Afrikaans or Fanagalo.

In relating his experiences during his twenty years of active underground mining deep under Johannesburg’s bustling skyline, where he personally experienced the pick-and-shovel heartbeat that kept the industry going he pays tribute to the unsung heroes of mining, the men who went deep down in mineshafts at some considerable risk to break hard gold-bearing rock and to deliver it to gold processing plants.

The Golden Crown of Johannesburg’ is an unusual book in many respects. It is factual, informative and entertaining.

Written in the matter-of-fact style of a practical mining man, the book should appeal to anyone who has ever had anything to do with mining and to readers who are fascinated by gold and stories about the real heroes of mining, the mineworkers who risk their lives by going deep down the earth

The Golden Crown of Johannesburg contains more than 100 historical mining photographs; more than twenty true stories about acts of bravery carried out by mine rescue teams; narrow escapes and disasters; humorous incidents, and even witchcraft.

In his description of his family life in a mining community he also mentions how, because of living in close proximity of Crown Mines ‘native’ labour quarters, the family from Germany was introduced to the African way of life.

As a member of the stringently selected Chamber of Mines Proto Team, he took part in numerous emergency and rescue actions involving trapped and injured miners on the Reef mines in and around Johannesburg and Free State mines.

There is a section devoted to frequently asked questions about gold, gold mining and gold products.

The resumption of mining operations on the Central Rand by Central Rand Gold (Modern Mining, January 2008) will be celebrated through the launch of a new book about South Africa’s – and the world’s – most famous gold mine, Crown Mines. However, this is no conventional history of a mine; this is the story of his life as a miner on Crown Mines of a German nobleman Baron Gerhard von Ketelhodt. Von Ketelhodt did not choose the easy road in life; he chose the road least travelled, that of a miner in the most hostile working environment on earth – a deep South African gold mine.

Yet far from complaining about a difficult life under arduous conditions, Von Ketelhodt lived his new life in South Africa as an adventure filled with excitement and discovery, camaraderie and triumph in adversity. He recounts his story with freshness and verve and it is a tribute to all those who have worked on the South African gold mines and contributed so much to the building of modern South Africa and our great city, Johannesburg.

Despite these difficulties, von Ketelhodt thrived in his new environment. He married his wife, Erika, also a German immigrant in the Friedenskirche in Hillbrow and they had four sons. Not content with the daily challenges of his job, he sought further service to the industry through joining the Proto Team at Crown Mines, a fire and rescue team which was available at all times for rescue operations on any gold mine in South Africa.

The stories and anecdotes in the book will resonate with all those who have worked underground on the South African gold mines and will fascinate those who haven’t. The author also sketches the background to the Crown Mine’s operations within the context of the industry and the life of the times and he describes with nostalgia and sadness how the relics of the past glories of the mining era such as shaft headgears have been replaced by the mundane features of modernity such as motorways and factories.

This is a valuable contribution to Africana and our cultural heritage. However, there remains much scope for further research and it is hoped that the work will be expanded in a subsequent edition to add a more formal and detailed history of the mine to Von Ketelhodt’s personal experiences.

The mining industry is unlikely to achieve its safety targets unless it looks beyond mining for solutions.

That's the view of Inus Dreckmeyr, MD of Proudly South African electronic research and development house, Netshield SA, who believes that advances in the Information and Communications Technology (ICT) sector - particularly in the wireless arena - could provide some answers.

Dreckmeyr notes that the Mine Health and Safety Council's (MHSC's) latest annual report which was tabled in parliament recently lists machinery and transport accidents as responsible for the second highest number of fatal accidents on mines, after rock-related incidents. Factors that influence the contribute to the high number of accidents include an increase in the number of seismic events and the amount of moving machinery being used on the mines, as well as human behaviour.

"Much of the focus on mine safety, most research and a high proportion of the safety budget, is directed at reducing rock-related accidents. But mines also need to direct more attention at reducing locomotive and transport accidents. Using radar, wireless and smartcard technology innovatively, could go a long way towards reducing - if not eliminating - many of these accidents," he says.

According to Dreckmeyr, mines use warning signs and signals to indicate the existence of collision danger zones. This, he feels, is not enough as there may be a problem with visibility.

"In addition, when someone sees something often enough - such as a warning sign - its impact wanes. And if the driver is not concentrating, he may not see it at all," he says.

A solution, he suggests, would be to install a system that provides an audible and visual signal of impending danger - to be activated only when such danger exists. In other words, instead of drivers having to stop at a particular spot every time they pass it in order to check for oncoming traffic, a system could be implemented that will sound and flash a warning only if there is traffic approaching.

The same technology could be employed to force drivers to slow down when travelling too fast or approaching danger zones, or to prevent them from inadvertently getting too close to other objects or people.

"Netshield is currently developing such a system which we expect to launch later this year," Dreckmeyr concludes.

The winners of the second annual Nedbank Capital Green Mining Awards, which seek to acknowledge and celebrate the contribution that responsible mining and mineral beneficiation makes to the economic development of Southern Africa, were announced last night at a ceremony at Nedbank's head office in Sandton.

The winners are: Amandelbult Platinum Mine for its Amandelbult Environmental Management System in the Environmental category; Ekapa Mining for its Flamingo breeding island at Kamfers Dam in the Limited Resources category; Anglo Coal for its Basa Njengo Magogo Vosman alternative fire-lighting project in the Socio-economic category; and Anglo Coal and BHP Billiton Energy Coal South Africa (BECSA) for the Emalahleni Water Reclamation project in the Sustainability category.

Mark Tyler, head of Mining & Resources at Nedbank Capital says: "We were encouraged by the standard of the winning projects for this year's awards - Ekapa Mining's Kamfers Dam and Anglo Coal's Emalahleni Water Reclamation projects in particular, are world class. Entries were welcomed from the entire African continent this year, but for now, the winners' trophies remain on South African soil.

"The response to this year's awards indicates that awareness around sustainability has increased, and that more and more mining companies are striving towards a more sustainable future for their mines and those communities affected by them. We encourage and look forward to entries from the junior, mid-tier and major mining companies for the awards next year," said Tyler.

The Environmental category winner, Amandelbult Platinum Mine's Environmental Management System, was recognised for the positive impact it has had on both the mine and the community. Since 2000, Amandelbult Mine has implemented a sustainable Environmental Management System (EMS) to continually improve on its environmental risk identification and impact management. This initiative reaches beyond compliance; the EMS has been integrated into the entire operation and has been extended to benefit communities beyond the mine boundaries. This has resulted in more sustainable practices both at the mine and within the community. Other positive elements of the EMS include effective education of employees, contractors and local school learners; environmental and species protection; partnerships and the inclusion of community input and involvement; and job creation.

Ekapa Mining received the Socio-Economic Award for its exceptional Flamingo Breeding Island at Kamfers Dam Project. This majority black-owned junior mining company, based in the Northern Cape, sponsored, designed and constructed an artificial flamingo breeding island, the first such structure in Africa, in order to contribute to the conservation of the continent's threatened Lesser and Greater Flamingos. The project is a unique, world-class contribution to saving a threatened species. Other commendable aspects of the project include the strong partnership approach which involved local government and local community organisations; an innovative approach to the design of the artificial breeding sites; positive socio-economic impacts, such as tourism and strong biodiversity benefits, principally species protection; and the fact that the project has research, education and tourism potential which Ekapa Mining could consider enhancing further.

Anglo Coal's Basa Njengo Magogo Vosman Alternative Fire-lighting Project, winner of the Socio-economic category, was recognized as an exemplary example of a simple, low technology solution to a major health and social issue. High levels of air pollution associated with household coal burning are known to create severe health and environmental problems, especially during the winter months when coal is not only used for cooking, but as an essential heating source. Although it does not sell coal to households, Anglo Coal elected to promote a low-cost coal burning intervention that teaches families to make fires in a much healthier, more cost effective and environmentally friendly way. Anglo Coal adopted an innovative approach to awareness raising by using a community member as the role model. This together with appropriate, effective communication tools and good community engagement has ensured a high adoption rate from people exposed to the method. Household cost savings, reduced air pollution and reduced health impacts have also resulted from the initiative.

Anglo Coal and BHP Billiton Energy Coal South Africa (BECSA), the winners of the Sustainability Category, were lauded for their Emalahleni Water Reclamation Project, labeled a 'world-class project and an exemplary model for development in the Nedbank Capital Green Mining Awards Sustainability Category' by the adjudicators. The companies, in a pioneering private-public partnership also involving the Emalahleni Local Municipality, initiated a project to remove water from the underground workings of four mines and to desalinate it to potable quality for supply to the water-stressed municipality's final reservoirs. The project addresses the mining and environmental liabilities associated with polluted underground water, and benefits the local community by supplementing the currently low domestic water supply. Once operating at full capacity, the plant will meet 20% of the local authority's daily water requirements. With substantial growth taking place in the Witbank region, this project assists in meeting growing municipal, commercial and industrial water needs

Issued by Nedbank Media Relations

Thabazimbi Projects R2.5 Million Savings Using Locally Developed Dust Suppressant

Thabazimbi mine anticipates a saving in excess of R50 000 per month as a locally developed dust suppressant product is being utilised on the pit's road surfaces in their Kwaggashoek East open pit section.

The product, Roads Environmental Dust Suppressant (REDS) developed locally by Samchem, is being tested over a six month period.

The tests, which began a month ago, are already showing impressive results at the Kwaggashoek East open pit, one of four pits.

On water usage alone there are savings of up to ninety six percent, saving over 5,5-million litres of water per month.

"Using water as a dust suppressant needed 128 trips per month in a bowser truck, with each trip having a distance of up to six kilometres and 45 000 litres of water used on each trip. We now only do one trip a week, over weekends, which does not disrupt the normal days work," says mine pit superintendent Grant Crawley.

"The monthly savings of R50 000 exclude water usage and only covers diesel savings, vehicle maintenance and tyre wear and tear. If we included water savings the figure would be significantly higher."

"There are benefits also to the environment, to employee health and overall safety. The product bio degrades in thirty days."

"In terms of safety, high levels of dust have been known to cause vehicle collisions, and excessive dust affects employee health," says Crawley.

"Water is currently being applied in the other pits. It needs to be applied up to six times a day. REDS is also more cost effective than other products which are not biodegradable, are more expensive, use more water, require a specially developed douser vehicle and can cause damage to vehicle paintwork and tyres."

"Overall, using REDS at all four pits could see savings of over 2.5-million per annum," says Crawley.

Contact: Belinde Mans
Administration & Marketing Manager
Samchem Drilling Fluids & Chemicals
Tel: + 27 11 908-5595
Fax: (011) 908-5887

Andrew Evans, Industrial Lubricants Marketing Manager at Shell Lubricants South Africa discussed how the changing needs of the coal mining industry are putting the spotlight on effective lubricant management to help maintain productivity.

Lubrication has long been the hidden hero of the coal mining industry; essential to the smooth running of the mine, yet rarely seen as key to productivity.

Over the past three years however, with the soaring price of coal and the resulting pressure on operators to increase output, effective lubrication has become more important than ever. And the challenge to lubricant suppliers is to address the sector’s changing needs with on-the-ground technical support, ancillary services and targeted product development.

“The rising price of coal is great news for the coal mining industry and has led to lots of investment,” explains Evans “but essentially it means that operators are using the same equipment to produce coal at a much more intensive rate.

“Equipment utilisation, reliability and availability are key factors in gaining optimum operating hours between service intervals, which put extra pressure on the lubricant to perform. It is also prompting operators to try to run machinery for longer without a service break.”

Shell Lubricants SA have discovered that many coal mine operators are now attempting to increase certain component life from 16,000 hours to 20,000 hours. “A 25% increase in the working life of components is an extremely ambitious target and, where it is achievable, it can have significant cost benefits,” Evans continues. “However, it also carries considerable risks, including component failure and oil break down. Either of these scenarios can result in unscheduled and expensive production stoppages/losses that may outweigh the financial gain of extending component life, increasing rebuild intervals and driving greater throughput.”

In addition to achieving production efficiencies by driving component life to its limits, operators are also trying to maximise production rates by extending service intervals and, therefore, extending oil drain intervals. “On the face of it, extending oil drain intervals can help achieve significant production efficiencies as it reduces stoppages. However, it also increases the risk factors,” comments Evans. “The lubricant is required to work harder and longer to protect components over a longer time period, so its effectiveness will decline, just as the need for effective lubrication of components increases. Unless the right lubricant is used and carefully monitored, the end result can be unscheduled stoppages – just the opposite of what the operator is trying to achieve.

“As one of the essential elements of equipment efficiency, effective lubrication management must be factored in to production efficiency programmes, and more and more mine operators are calling on the expertise of their lubricant supplier to help them achieve their output goals.”

The first step in pushing equipment longer and harder to increase productivity is to ensure the lubricants used have the high performance capabilities to cope with more intense production levels.

“Even with a high quality lubricant, the risks of extending oil drain and service intervals and increasing component life are high if the lubricant’s effectiveness is not carefully and regularly monitored. Oil Condition Monitoring (OCM), not only allows the operator to identify any shortcomings in the lubricant’s efficiency, it can pinpoint any abnormal trending or wear rates, giving the operator an indication of whether they might be pushing their equipment too hard.”

OCM involves the analysis of oil samples taken at specific points in the equipment at regular intervals to monitor changes in the lubricant that could indicate current or potential problems with the equipment. Evans explains: "When studied by Shell Lubricants experts, the condition of the oil, the pace of its deterioration and the presence of contaminants can all provide indicators of equipment performance. This analysis can be used to provide a simple traffic light status of the equipment's condition and recommendations of what preventative action needs to be taken and when."

Implementing an OCM regime supports extended oil drain and service intervals by reducing the risk of resulting maintenance problems going unnoticed. Evans continues: “While avoiding scheduled downtime can help increase production levels, unscheduled downtime can have an adverse affect on overall output, particularly where mines are remote and may have to wait for a service engineer or new components to arrive on site. OCM allows operators to manage this risk by picking up potential problems early enough that maintenance can be scheduled in before unplanned stoppages and reactive maintenance is required.”

The effectiveness of OCM relies on the sampling methodology and the accuracy of the resulting data. Shell’s mining specialists work with customers to ensure that they get this right from the very beginning. This process usually begins with a Shell Lubricants expert recommending the right product for the equipment and operational requirements. With the correct products in place, the next step is to ensure operators are trained to carry out the lubrication programme correctly. In addition, operators are extensively trained in sample-taking methods and Shell Lubricants recommend the appropriate set of tests for each application to establish a suitable OCM programme.

Results of OCM analyses provide to the operator with risk alert; allowing them to know whether the lubricant and equipment are working effectively, alerting them to a potential problem highlighting an existing issue that must be addressed immediately.

Evans continues: “OCM programmes are tailored to meet the customer’s specific needs. We discuss the operator’s productivity objectives with them and design a lubrication management system that will help support their goals so that any risks they take in driving their equipment are calculated and carefully monitored.”

For as long as operators can benefit from the high demand for coal by increasing production levels, the question of how to drive productivity without damaging profitability through unnecessary reactive maintenance will continue to challenge the industry.

“There is no single answer to how intensively a mine can produce before it runs into problems, as every site is different,” adds Evans “but for operators that understand the vital role that lubricants can play in both enhancing equipment efficiency and revealing potential faults, lubrication can play an important role in managing the risks of extending component life, and increasing service and oil drain intervals.”

Issued For: Shell SA
Contact: Andrew Evans, Industrial Lubricants Marketing Specialist: 011 996 7264
Email: a.j.evans@shell.com Website: www.shell.com

Leading safety company, MSA Africa, is the first in South Africa to launch the all new AO Safety Light Vision LED safety spectacle, the first industrial eyewear designed with integral hands-free lighting.

This innovative safety spectacle provides the benefit of safety and lighting, Light Vision eyewear can be used in all industries where extra light is required, including machinery or automotive repair, medical, emergency services and lab work, wire junction boxes, night rescue and police search.

The glasses are designed to offer all the protection of standard safety eye-wear. They provide wide coverage, and their wrap-around shape protects against flying particles. The lens is made from impact resistant polycarbonate with anti-fog coating and the soft rubber temples and nose pads offer comfort for extended wear.

The hands-free lights, conveniently positioned on the temples of the glasses, comprise an ultra-bright LED system. They have a swivel mechanism to facilitate directional lighting, and a long battery life of up to 50 hours. For extra convenience the batteries are also easily replaceable.

For further information, please contact MSA Africa on (011) 610 2600 or visit www.aosafety.com.

Failsafe new technology allowing people to be identified by their veins can save South African mines millions of rands each year. Vein scanners are faster and more effective than fingerprinting.

The scanner "reads" a person's veins through a photo and heat process. Just as everyone's fingerprints are unique, their heat emission and vein patterns are similarly unique.

"The greatest advantage of this sophisticated and affordable system is the speed and accuracy with which people can be identified," says DexGroup Informatix's Jans Wessels. It is possible to identify a person in less than half a second, and the system is 99% accurate.

There are also the time saving advantages - the number of people underground can quickly be determined in cases of mine accidents or earth tremors.

Vein scanners can also be used to ensure that miners have undergone medical examinations. The new technology can deny a miner access in the canteen or a shaft if he has not gone for a medical examination.

Biometric or fingerprint technology is also difficult to apply because of "damaged" fingerprints or grimy fingers.

The new technology can play an important role in cost saving in mining, fraud committed by wages paid to ghost workers, unauthorised use of mine canteens and the management of equipment and clothing handed out free by the mine.

Although most mines in South Africa exercise relatively strict first phase access control, they are often vulnerable when the first point of control has been passed. Industrial espionage is also possible owing to unauthorised entry. Vein scanners prevent "buddy clocking" and can be applied in conjunction with conventional clock systems. The technology is also highly effective in conjunction with card access systems.

The system is currently being tested at some of the largest mines in the country.

The advancements made in the development of electronic sorting technology have made it very versatile in its applications. In 2003/4 one such application was commissioned at the TanzaniteOne mine in Merilane,

Tanzania

The uniqueness of this application is underlined by the fact, that the world’s only known source of Tanzanite is situated in the Simanjiro district of Tanzania, 70km south-east of Arusha and 16km south of Kilimanjaro International Airport.

Tanzanite is located in a relatively complex geological environment and is found in ‘chocolatetable’ boudin structure, typically located in the hinges of isoclinal folds (folds dipping in the same direction) present in the ore body. The Tanzanian government demarcated the tanzanite mining area into 4 Blocks: A, B, C and D, measuring approximately 5km by 2 km in total. The TanzaniteOne Group owns the mining licence for the largest area, Block C.

Geological tests have revealed that the supply of gemstones will be exhausted within approximately 15 – 20 years.

Tanzanite is a gemstone variety of the mineral zoisite. Zoisite’s occurrence in the presence of vanadium (and hence the formation of tanzanite) is exceptionally rare.

Tanzanite is mined underground, via production drives that extend from decline shafts, running on dip of the ore body. The ore is hoisted to surface from where it is transported by truck to the plant.

A screening and crushing process reduces the material to a -30mm size fraction, before it enters into a dense media separation (DMS) process to recover the denser tanzanite (SG 3,35). The DMS floats are discarded, whereas the DMS sinks is collected in a skip which tips the concentrate onto a slide entering the recovery room.

Picture 5 shows the block plan of the sorting plant. The DMS concentrate is screened on a tripledeck Sweco washing screen, so that the feed for the sorting machines is in a size range ratio of not more than 3:1. The washing of the feed material is very important as it removes all the dirt and dust off the particles, so that the true surface colours of the stones are exposed to the camera system of the sorters. These size fractions are then fed to two MikroSort ConcSort BSX-063 machines via two 600 mm wide pan feeders. The first ConcSort BSX-063 processes 240 kg/h of material with a size range of -30 mm +12 mm. The second unit incorporates two tracks, one to sort 210 kg/h of material with a size range of -12 mm +5 mm, and the other to sort 150 kg/h of -5 mm +2 mm.

The fine material (-5mm +2mm) is dried by means of hot air blown onto the feeder. This prevents lumping of the feed material which would have a marked impact on the sorting efficiency in this size range. The coarse +5mm material is fed to the sorting in a drip dry condition. The moisture on the stones in this case is important, as it enhances the natural colours of the ore.

• 4 off conveyor belts for the supply of the feed material to the MikroSort machines

The working range of the compressor station is set between 4.5 and 7.4 bar. The two sorters are set at different pressure level: Sorter 1 (-30mm +12mm) at 6,5 bar; Sorter 2 (-12mm+2mm) at 5 bar.

The belt speed of both sorters are set at 2,75 m/s. The total power requirement for the sorting plant is approximately 60kW.

The sorters are fitted with a dual illumination system to utilize the reflected light properties as well as the transparency properties of the particles.

The example of the sorting algorithm is illustrated in picture 12. It shows the settings to separate the above rock types by using a combination of colour and brightness of both the reflected and transparent light properties of the material.

Two MikroSort machines have been commissioned in the sort-house at TanzaniteOne Mining Ltd, producer of the world’s rarest coloured gemstone, tanzanite. The mine is located in the foothills of Mount Kilimanjaro in

Tanzania

. The opto-electronic sorting technology is substantially improving recovery efficiencies, throughput and security within the sort-house at the mine.

The sorting plant is used for separating tanzanite fractions from waste by colour and transparency, two of the many optical properties that can be used to programme the MikroSort machines.

Tanzanite bearing material from the heavy media separation plant is washed and screened on a tumbler screen before being fed to two MikroSort ConcSort BSX-063 machines via two 600 mm wide pan feeders. The first ConcSort BSX-063 processes 240 kg/h of material with a size range of -30 mm +12 mm. The second unit incorporates two tracks, one to sort 210 kg/h of material with a size range of -12 mm +5 mm, and the other to sort 150 kg/h of -5 mm +2 mm. TanzaniteOne Mining sort-house’s MikroSort system is meeting the production requirement for which it was developed. 80% purity with a 98% recovery rate is being achieved. The product lost is low grade tanzanite that has no colour or crystal structure.

Source:
Lütke von Ketelhodt, Johan Jacobs
Firma/Hochschule – IMS Engineering (Pty) Ltd – MikroSort Division
Straße – 6 Eastern Services Road
PLZ, Ort – Eastgate Ext. 3, Sandton 2199,

South Africa

E-Mail: lvonketelhodt@mikrosort.co.za

[1] HARTWIG, I. (2002): Test Report, Separation of Tanzanite (High and Low Grade) from Concentrate Tailings, Wedel

[2] WIEHL, K. (2004): MikroSort Machines for AFGEM, Product Function Specification.

[3] BROOK BROWDE COMMUNICATIONS, (2005): MikroSort – Unique Recovery Process for Rarest Gem.

[4] BANCROFT P. (1984): Gem&Crystal Treasures, Western Enterprises/Mineralogical Record, Fallbrook, CA, 488 pp.