Menzel Elektromotoren has designed and manufactured three powerful 6600 V squirrel cage motors as integral components for pit fans. The customer specified cylindrical motor casings as compact as possible. The greatest challenge was to implement the required rated power of 1700 kW in cylindrical casings. Menzel therefore designed fin-cooled motors (cooling type IC 411) in frame size 630, an extremely unusual design for motors this large. The manufacture is complex but the result is optimal for the constricted installation conditions. In order to save additional space, all connection cables are routed out of the motors and the terminal boxes are mounted outside the fans. Since the driven fan wheels are mounted directly on the motor shafts, the motor bearing must compensate additional high loads: radial loads up to 20700 N and axial loads up to 27000 N. For the required bearing service life of 100,000 hours, Menzel implemented a special rolling bearing setup. In addition, the motors have a second shaft end for a holding brake. The three-phase squirrel cage motors are designed for operation on a frequency converter (duty type S9) with speed changes and reversal of the rotation direction. This allows the pit fans not only to ventilate the mine, but also to extract dangerous firedamp if necessary.

Surface-cooled motors from Menzel: https://www.menzel-motors.com/slip-ring-motor/ic411/

The Nigerian government says it has agreed to pay $496 million to settle a multibillion dollar claim by Global Steel Holdings Limited over the control of Ajaokuta Steel Company.

Attorney-General Abubakar Malami said the federal government will pay the company $496 million instead of $5.258 billion demanded by the firm, to settle the dispute. The deal was reached under the alternative dispute resolution framework of the International Chamber of Commerce, said a statement by Mr Malami’s spokesperson, Umar Gwandu.

The dispute followed the federal government’s revocation in 2008 of an agreement that handed control of the steel works and the National Iron Ore Mining Company to Global Steel Holdings Limited, an Indian firm. In cancelling the deal, the Umar Yarádua administration said the terms of the concession at the time were not favourable to the country.

The steel company, located in Kogi State, was conceived to serve as the pillar of Nigeria’s industrialisation. It was built by the Soviets between 1979 and the mid-1990s but has never produced steel as the project was never completed. It was also mismanaged.

The government said the seeds of the disputes can be traced to five contracts entered between 1999 and 2007 that gave complete control over the Nigerian steel space to one company group, Global Steel group.

The justice ministry said the decision to terminate the contracts by a new administration in 2008 was taken contrary to legal advice by the Federal Ministry of Justice, which cited the termination cost in the form of damages. It said had the government waited for 55 days, the pact would have terminated lawfully and the government would have collected more than $26 million from Global Steel.

“This was because the firm appeared unable to pay the first tranche for the Ajaokuta shares before the first anniversary of the agreement (25 May 2008),” the statement said.

“This failure would have given Nigeria a right to over $26m as liquidated damages under cl.12 of the Ajaokuta Share Purchase Agreement.

“Global steel, in consequence, took the federal government to the International Chamber of Commerce, International Court of Arbitration, Paris, commencing arbitration in 2008. Although the Federal Government negotiated a settlement in May 2013, the previous administration failed to implement its settlement agreement,” the statement said.

In May 2020, Global Steel threatened a resumption of the arbitration and announced an anticipated claim in damages of over $10-14 billion against Nigeria.

The government said it agreed to pay over $400 million to settle the case once and for all after engaging PwCNigeria to do a comprehensive review to ensure taxpayers are protected.

With this development, the statement said President Muhammadu Buhari has now “rescued the steel industry from interminable and complex disputes as well as saving the taxpayer from humongous damages.”

“The Office of the Attorney General of the Federation and Minister of Justice grappled with the inherited problem by adopting a blueprint of seven principles for the cost-effective resolution of contractual disputes wherever they occur. They are the use of institutional mediation, choice of FGN counsel, the use of financial advisers with reputational capital, the importance of not discouraging foreign investment, fiscal responsibility, transparency, and the recognition that joined-up government produces superior outcomes,” Mr Gwandu said.

South African based vibrating screen and feeder original equipment manufacturer (OEM) Kwatani reports that orders for its equipment have surged in recent months to record levels, with orders coming not only from South Africa and the southern African region but also overseas markets.

“The current level of business is the best we’ve ever seen since the company was founded nearly 50 years ago and every month now is turning out to be a record month,” says Jan Schoepflin, General Manager Sales & Service at Kwatani. “The growth is quite astonishing – in fact, 50 to 60 %, year on year.”

He adds that Kwatani is currently producing around 60 machines a month. “To keep pace with demand, we’ve rented an additional 3 000 m² of factory space to complement the 17 000 m² we already have,” he says. “Being part of Sandvik Rock Processing Solutions, which in turn is a business area within the Sandvik Group, we’ve also been able to outsource some production to other Sandvik factories overseas, including Sandvik’s Indian factory.”

One of Kwatani’s current orders – won in the face of intense opposition – involves the supply of over 70 screens and associated equipment to a large copper mining operation in Central Asia. This is the largest order in Kwatani’s history and probably the largest single screen order ever to be won by a screen manufacturer based in Africa. “We’re expecting another large order from this region shortly – it won’t be quite as big but will still be very substantial,” says Schoepflin.

Kwatani is also busy with two big contracts in southern Africa, one for a major platinum mine in South Africa and the other for a zinc project in the DRC. Both projects are in the construction phase.

According to Schoepflin, the surge in sales reflects not only more buoyant conditions within the global mining industry but also Kwatani’s membership of the Sandvik Group.

“We became part of Sandvik at the end of 2021 and this has opened many doors to us,” he says. “We’ve always been big in Africa and were, in fact, already ranked as the biggest screen manufacturer on the continent prior to being acquired by Sandvik but were less strong in certain other parts of the world. Being part of Sandvik has given us improved access to many markets, particularly in South America where Sandvik is the dominant supplier of mining equipment.”

Schoepflin also points to the quality of Kwatani’s products as another reason for the skyrocketing demand for its equipment. “We produce bullet-proof products that work reliably and efficiently and that have been proven in Africa’s mining areas, which are probably the toughest in the world in terms of the demands placed on machines,” he says. “Equipment that works well in Africa will perform anywhere.”

He adds that the fact that Kwatani’s equipment is manufactured locally is another major plus for the company. “Our manufacturing costs here in South Africa are low by global standards and our exports also benefit from the fact that South Africa’s currency, the rand, is very weak. The result is that our machines are very competitively priced.”

Kwatani forms part of Sandvik’s crushing and screening division within Sandvik Rock Processing Solutions. This now includes not only Kwatani and Sandvik’s own screening business but also the recently acquired mining related business of Schenck Process Group, making Sandvik the world’s biggest supplier by far of vibrating screens and related equipment.

As miners continue to work long-hours in consecutive shifts, today’s heavy mining equipment – for both underground and overground operations – is in operation 24/7 to meet tight work schedules.

Operating in a high-risk environment; with dust, prolonged vibration and extended use, all elevating risk of overheating, these heavy-duty mining vehicles are inevitably prone to fire risk.

Fredrik Rosén, business manager, Dafo Vehicle Fire Protection, explores the fire risks associated with heavy equipment at mines, especially as vehicles and technologies evolve, and explains how mine operators can minimise downtime, while maximising safety.

What’s influencing fire risks?

Specific risks will be determined by individual risk assessments, which look at a mine’s operations as a whole and how vehicles operate in a particular environment. The majority of heavy-duty vehicles and equipment, though, are at risk from several common fire hazards in mines.

Overheating

Due to the challenging operating environment, mine vehicles inevitably gather dust and dirt. Undoubtedly, keeping the engine compartment clean reduces risks, but doing so might be difficult in some industries, like mining, where operations generate a lot of dust. Unchecked, though, this could increase the risk of overheating.

Overheating on its own isn’t necessarily a sign of a potential fire. But due to the extensive operation of mining vehicles, prolonged vibration can increase the friction between different sections of the vehicle, resulting in increased wear and tear, as well as an increased risk of overheating.

If this wear and tear leads to loose cables, sparks or damage to the injection pipe, for example, combined with overheating, it can result in dangerous electrical or spray fires that are violent and quickly spread.

Electrification

In an effort to be more ecologically friendly, several mine operations are transitioning from conventional combustion engine vehicles to electric vehicles (EVs).

Although EVs are less likely to overheat, their lithium-ion batteries do present a unique fire risk. The four factors listed below are the primary reasons for battery fires:

• Heat exposure
• Mechanical impacts, such as collisions or mechanical failures
• Overcharging or undercharging
• Protection flaws, where particles can enter battery cells.

Each of these has the potential to result in internal short circuits, putting the battery at a high risk of thermal runaway, which is characterised by a quick rise in temperature and the subsequent risk of fire, release of toxic gases and possibly even enormous explosions.

Thermal runaway is typically unnoticed by traditional fire detection systems until temperatures start to increase, by which time they’ve frequently passed the point of no return. As a result, there’s a need for a unique detection and suppression solution that recognises the release of toxic gases before temperatures rise.

Automation

Accelerated by the COVID pandemic, mining automation has reached an all-time high. Remotely operated autonomous vehicles can now be used to boost uptime and reduce worker health risks.

However, when there are fewer persons present or nearby when mining vehicles are in use, it may be more challenging to spot fire threats. In this situation, an automated detection and suppression system is necessary to enhance response times, reduce the chance of downtime and avoid vehicle damage.

How can mine operators reduce the risks?

Recognise the particular risks connected to your mine first. As technology develops, keep re-evaluating your risk assessment map, as well as your systems for fire detection and suppression.

Whether a vehicle is electric, diesel, automatic or manual, there are distinct risks associated with each type that must be carefully addressed.

To effectively manage the relevant threats, maximise safety and save downtime, you should consider the whole mining operation and develop a customised solution.

For more information, visit Dafo Vehicle Fire Protection.

A professor of Metallurgical and  Minerals Engineering at the Federal University of Technology Akure FUTA, John Ade Ajayi ,has lamented that Nigeria has been unable to utilize its  abundant mineral resources to create sustainable wealth and drive real  development that impact the people. Ade Ajayi made the submission while delivering the 146th Inaugural lecture of the Institution with the title: “Rich Nation, Poor People! The king of Metals as Paradigm: Quo Vadis Nigeria?” on the 10th of January 2023.

He said Nigeria is blessed with a lot of non-ferrous minerals including copper ores capable of contributing immensely to the Gross Domestic Product, GDP of the country. He however lamented that in spite of the abundant mineral resources there is hardly any serious actual mining capable of making Nigeria an industrialized nation. According to him,” There is no single functional and sustainable mine, mill or metal extraction plant in Nigeria. The National Iron Ore Mining Company, Itakpe, Mine and Mill are not really operational for now. The only tin smelting plant in Nigeria, Makeri Smelting Company, Jos has gone into the dustbin of history. What is prevalent is artisanal mining and ‘processing’ and quarrying. “He described the operations of artisanal miners as, “Unscientific, untechnical, uneconomical, unsafe, unhealthy and environmentally unfriendly.”

Professor Ade Ajayi   said there was an urgent need for government to lead the drive to chart a new direction for sustainable mineral resources development that will engender economic prosperity in Nigeria through correct policies. He said the economic development of any nation depends considerably on its level of industrial development and this in turn depends invariably on the level of mineral exploration and manufacturing activities in the national economy. He said concerted effort must thus be taken to revive industries and set factories working through minerals and metals value chain in Nigeria to improve the quality of life of its people.

He said the importance of iron and steel production in the national economy like Nigeria cannot be overemphasized as it is presently recognized that a nation that controls iron and steel controls the world. To this end he recommended that a Council for the Nigerian Institution of Mining and Metallurgy (CNIMM) be put in place in accordance with international best practices to see to the sustainable production of non-ferrous metals required for the production of ferro-alloys and different types of alloys.

Ade Ajayi , Nigeria’s first professor of metallurgical and minerals engineering , said in order to be able to sustainably produce mineral and metal products for the use of the society, the Nigerian mining, minerals and metals (3M) industries should have viable linkages with academic institutions and research institutes. He said the 3M industries are to produce goods and services for the society thereby generating employment, creating wealth and engendering national economic development. The Don called for a clearly convergent point between inventors and investments in Nigeria such as science and technology parks for startups.

He recommended that FUTA as the best university of technology in Nigeria should be declared as a centre of excellence in Mining engineering, mineral processing technology and extractive metallurgical engineering. According to him, there is the need to transform the Nigerian universities from the present intellectual amnesia to intellectual revolution.

Ade Ajayi advised that competence enhancement and training should become the hallmark of those driving the country’s policies saying, “The funds used for junketing and seeking international investors can be used for training and research. For national interest, we must reorder our priorities.”

The Vice Chancellor, Professor Adenike Oladiji, in her address said Professor Ade Ajayi has been a consistent productive scholar, a metallurgical engineering expert and an educational manager per excellence. She said Professor Ajayi had contributed significantly to knowledge in his chosen area of Metallurgical and minerals engineering.