CHART HOWDEN: Cooling the Deepest Mines on Earth

Some engineering challenges are measured in metres, some by time or size, others in degrees. At Chart Howden Projects, all apply in equal, unforgiving measure. The company’s business is keeping air moving and temperatures survivable in mines that reach further underground than almost anywhere else on the planet, where virgin rock temperatures can exceed 60 degrees Celsius before any cooling system is switched on. It is a niche that few can occupy, and one that Chart Howden has spent decades perfecting across southern Africa.

Howden’s roots in the region stretch back more than 80 years, with a presence in deep-level mine cooling dating to the 1960s, when Johannesburg became, and remains, the unofficial global centre of excellence for the discipline.

In 2023, Chart Industries acquired Howden, folding a recognised industry leader in air and gas handling into a broader group already active in cryogenics, liquefaction and thermal management. That combination has proven complementary rather than disruptive, opening new markets in LNG and cryogenic gas storage for the southern African business while leaving its core mining and power work untouched.

Group ownership has since changed again. In July 2026, Baker Hughes completed its acquisition of Chart Industries as the group’s third operating segment alongside its existing oilfield and industrial businesses. Baker Hughes Chairman and Chief Executive Officer Lorenzo Simonelli said the deal strengthens the group’s broader offering. “Chart’s thermal management solutions bring complementary capabilities and aftermarket service offerings that accelerate our portfolio strategy. Together, we will expand the solutions we deliver across a broader range of energy and industrial markets and create greater value for customers and shareholders. We welcome our new colleagues to Baker Hughes and look forward to working with them to deliver disciplined execution and maximize synergies as we move forward.”

Crucially for customers across southern Africa, the change in ownership is not expected to disrupt operations on the ground. Howden’s own account of its purpose remains consistent through the transition. “As a global leader in mine safety and air and gas handling solutions, we are committed to supporting safer, more efficient operations across the mining industry. Our innovative technologies continue to play a critical role in improving underground safety, ventilation and overall operational performance. Our technologies support reliable, resilient, and lower carbon power generation, helping operators across Africa meet growing energy demands while optimizing performance and sustainability.”

ENGINEERING APPROACH

Much of that reliability comes down to how Chart Howden Projects works. Kudzai Nyangoni, Managing Director of the division, explains the model behind every contract the company signs. “We execute all projects for customers on an EPC basis. From enquiry, we design and engineer solutions in house and then agree with the customer that our solution meets their requirement before moving to procurement and manufacturing. We have all manufacturing facilities within our group and we can manufacture all components that we consider our IP.”

There is no ‘off the shelf’ offering he adds. “Everything we do is bespoke and customised. Everything is manufactured with special materials depending on the environment in which the equipment will operate.”

That approach is visible across the region’s flagship mines. At AngloGold Ashanti’s Mponeng, the world’s deepest gold mine, extending more than four kilometres below surface, Howden has built up its cooling strategy in stages over decades, combining surface bulk air coolers, chilled water and a 12MW ice plant capable of producing 120 tonnes of ice an hour. The ice is used both to cool underground air directly and, through an Eskom-backed pilot, as a form of thermal storage, frozen overnight when power is cheaper and melted during peak demand to ease strain on South Africa’s grid.

Elsewhere in Gauteng, at Harmony Gold’s Doornkop mine, a deep single-shaft operation on the northern rim of the Witwatersrand Basin, similar ventilation expertise keeps a mature but still productive operation running safely more than a decade into its planned life extension. Further north, on the Zambian copperbelt, Howden was awarded the contract for what has become one of the largest underground mine cooling projects conducted in Africa in recent years, delivering roughly 38MW of refrigeration across Mopani Copper Mines’ Mufulira, Synclinorium and Mindola operations. General Manager for Mine Cooling and Compressors, Theuns Wasserman, describes the scale involved: “It is one of the biggest mine cooling projects in Africa in recent years and there is around 38MW of refrigeration going in on site. We were awarded the full turnkey project, all the way from civil and earthworks to mechanical and electrical installation, through to commissioning.”

Beyond South Africa and Zambia, Howden’s footprint extends across the continent’s gold belt. At Fortuna Silver’s Yaramoko mine in Burkina Faso, the company delivered an 8MW surface bulk air cooling plant, chilling ventilation air before it descends the shaft.

Similar principles apply at West African operations such as Avesoro’s gold mines, while in the coal sector, at Seriti’s New Denmark colliery in Mpumalanga, Howden’s air and gas handling technology supports the reliable power generation on which much of the region depends. Nyangoni notes that this reach reflects a wider group dynamic. “Time and again we are called upon by business units in North America, Asia-Pacific, or Europe to provide support for our colleagues. We have completed many projects in Eastern and Central Europe and South America where we have collaborated on projects using Chart technology, sending engineers to execute projects alongside local colleagues. We occupy a very niche position within the group and our experience developed in South Africa is second to none.”

WHY COOLING MATTERS

The stakes behind all of this work are rising. Underground temperatures increase with depth as a matter of physics, and as easily accessible ore is depleted, more of southern Africa’s mining activity is heading downward rather than outward. South Africa’s opening of Qala Shallows in December 2025, its first new underground gold mine in 15 years, illustrates the trend directly, arriving as record bullion prices make previously marginal deep and reopened operations commercially viable again. Without effective cooling, none of that ore can be extracted safely. Prolonged heat exposure raises the risk of heat stroke and impairs concentration in environments where a lapse can be fatal, while poorly managed ventilation drives up both energy costs and downtime.

That combination, rising depths, rising demand and rising stakes, is precisely why specialist cooling and ventilation engineering has become such a critical discipline rather than a peripheral one. It is not a problem that can be solved with standardised equipment or short-term thinking, it requires decades of accumulated expertise, a manufacturing base capable of producing bespoke, mission-critical components, and the willingness to keep innovating as mines push further into the earth. As ownership structures shift around it, from Chart to Baker Hughes, that expertise, built in South Africa and exported across the world, remains the constant that keeps some of the planet’s most demanding mines running safely.