Bab el-Mandeb at Risk: GEM Mining Warns a 90-Day Disruption Could Hit Up to 77.8 Million Tonnes of Critical Mineral Flows

Introduction

If you work in battery manufacturing, copper mining, or critical mineral procurement, a new analysis published this week should command your attention. On September 15, Chile-based GEM Mining Consulting released a scenario assessment of what a 90-day disruption at the Bab el-Mandeb Strait would mean for global mining supply chains. The answer, even in a conservative reading, is severe: between 38.9 million and 77.8 million tonnes of commodity and input flows at risk, with a central estimate of 61.1 million tonnes.

The timing matters as much as the numbers. Houthi forces seized the Yemeni port city of Mokha on September 10, took Perim Island, which sits inside the strait itself, on September 11, and within days had consolidated control of the Greater and Lesser Hanish Islands roughly 160 kilometres to the north. As of this week, Houthi fighters control Yemen's entire Red Sea coastline as well as the key island positions that allow them to monitor and threaten vessels approaching the chokepoint. The GEM analysis is not a theoretical stress test. It is a live risk assessment for a disruption that is already beginning.

The reason this matters beyond shipping markets is that critical minerals move through this corridor in both directions. Battery materials, chemical inputs for mine processing, explosives feedstock, and equipment spares all depend on Red Sea transit. A sustained blockade does not just delay a cargo. It can halt production at a mine that has run short of sulfuric acid, or strand a shipment of cobalt that a battery plant in Europe was counting on next month. The cascading logic of chokepoint disruption runs further than most supply chain models have been built to capture.

What the GEM Analysis Actually Says

GEM's assessment covers 15 commodity and input families and scores each one across six factors: route share through the strait, difficulty switching to alternative suppliers, inventory risk, current market balance, freight risk, and links to downstream industrial processes. Each factor is scored on a scale of one to five, with five indicating higher exposure. The result is what GEM calls an exposure heat map, a ranked picture of which commodity flows face the greatest combined vulnerability.

At the top of the vulnerability ranking sit petroleum products, liquefied natural gas, sulfuric acid, ammonia, specialty reagents, graphite, battery intermediates, rare earths, and equipment spares. These categories score highly because disruption does not just mean a longer route: it combines with limited inventories, concentrated supply sources, and the fact that some of these inputs have no easy substitute. A mine that needs sulfuric acid for heap leach processing cannot simply swap in a different chemical. If the acid is delayed or unaffordable, processing stops.

Larger bulk commodities, including iron ore, metallurgical coal, bauxite, and alumina, appear lower on GEM's heat map. These markets are deeper, alternative routes and suppliers are more available, and global inventories tend to provide more buffer time. That said, GEM notes that freight costs for these flows would still rise under a prolonged disruption, even if the risk of outright shortfall is lower.

The financial dimension of GEM's model is worth dwelling on. A value-weighted price-pressure range of 1.2 percent to 10.5 percent translates into associated cost premiums of $480 million to $2.48 billion across the 90-day scenario, with a central case estimate of $1.37 billion. For individual mining operators, the more immediate concern is not the aggregate figure but where that cost lands: higher delivered input costs, longer transit times, elevated insurance premiums, and increased working-capital requirements. These are not abstract financial pressures. They affect production guidance, operating margins, and in some cases whether a project can sustain operations at all.

The Geopolitical Escalation That Makes This Urgent

The Bab el-Mandeb is a narrow waterway, roughly 30 kilometres wide at its tightest point, connecting the Red Sea to the Gulf of Aden and from there to the Indian Ocean. Roughly 10 to 15 percent of global maritime trade passes through it, including an estimated 30 percent of container traffic between Asia and Europe. In the second quarter of 2026, according to U.S. Energy Information Administration data, 8.1 million barrels of oil per day transited the strait. That figure has grown in strategic importance since February, when Iran effectively closed the Strait of Hormuz, diverting more energy flows toward the Red Sea corridor.

This is the detail that transforms Bab el-Mandeb from a regional security concern into a global supply chain emergency. As I covered in my analysis of the Hormuz traffic collapse in September, the two straits are not parallel alternatives that shippers can switch between. They are sequential dependencies within the same export corridor. Cargo that cannot move through Hormuz has been redirected through the Red Sea. If Bab el-Mandeb is also severely disrupted, the rerouting option disappears entirely, and shippers face the long Cape of Good Hope detour: adding 15 to 22 days to transit times and materially higher fuel and operating costs.

Ana Subasic, a trade risk analyst at MarineTraffic, put the military geography clearly: the Houthi capture of Perim Island does not itself amount to full control of the strait, but it materially increases the group's leverage over the approaches. The subsequent seizure of the Hanish Islands tightened that grip further. MarineTraffic data for the week of the Houthi advance recorded 152 crossings from Monday through Thursday, with flows balanced at 76 entries and 76 exits. That traffic has not yet collapsed, but the pattern from late 2023 and early 2024 suggests how quickly sentiment can shift: the previous Houthi campaign produced a 55 percent decline in strait transits between November 2023 and February 2024, and a 90 percent collapse in Suez Canal container ship crossings over the same period, according to ITF and OECD data. Commercial shipping traffic through the Red Sea never fully recovered after that episode, even once the attacks paused.

Sulfuric Acid, Explosives, and the Inputs Miners Cannot Do Without

For most people outside the mining industry, the connection between a Red Sea shipping disruption and a copper mine in Chile or a lithium operation in Australia is not immediately obvious. The link runs through the chemicals and materials that mines require to function, inputs that are themselves traded commodities with their own supply chains and maritime dependencies.

Sulfuric acid is the clearest example. It is an essential processing input at copper, nickel, and cobalt operations using hydrometallurgical methods, including the high-pressure acid leach plants that have become central to battery-supply-chain strategy. Sulfuric acid is produced from sulfur, and roughly half of seaborne sulfur trade passes through the Strait of Hormuz. That flow has already been severely disrupted since February. China then suspended sulfuric acid exports in May 2026 as sulfur markets tightened, removing a major supplier from the spot market. Building on my analysis of the sulfuric acid crisis in September, the combined effect of the Hormuz closure and the Chinese export suspension has already produced significant repricing pressure across Latin America and Africa, the two regions most exposed to merchant acid markets. GEM notes the broad rule plainly: regions with captive smelter acid or sulfur-burning plants can absorb the shock better than regions relying on spot merchant cargoes. Chile, which combines structural acid deficit with mining concentration in the north and long seaborne supply chains, is particularly exposed.

Ammonia and nitrates feed the explosives supply chain, and specialty reagents used in flotation and leaching are often sourced from concentrated suppliers with limited alternative logistics. Equipment spares sit in a similar category: a critical spare for a grinding mill or an autoclave cannot always be sourced quickly from a different supplier, and delays in receiving it can idle an entire processing circuit. GEM's central thesis, stated explicitly in its August analysis of chain fragility, is that usable supply can fail even as mines continue operating, because bottlenecks develop elsewhere in the value chain. The September chokepoint analysis extends that argument into the logistics layer.

For Indonesia's HPAL nickel operations, the Hormuz closure has already produced severe disruption. These plants import approximately 75 to 80 percent of their sulfur from the Middle East Gulf. With that supply curtailed, Indonesian buyers have been competing with Chilean copper producers for smelter acid byproduct from Japan and Korea. Huayou has already cut output at its Indonesian plant by approximately 50 percent. A simultaneous disruption at Bab el-Mandeb would narrow the set of viable alternative supply routes even further.

Insurance, Freight Rates, and the Cost of Uncertainty

The financial mechanics of a chokepoint disruption work through several channels simultaneously, and they compound each other in ways that make the aggregate cost hard to predict from any single variable.

Maritime insurance prices for Red Sea and Bab el-Mandeb transits have already risen significantly. Cover generally remains available for many voyages, according to insurance analysts quoted in July reporting, but often on restrictive terms and at prices that can materially change the economics of a voyage. Some shipowners have continued to transit where freight earnings justify the additional cost. Others have declined even when cover was technically available, citing crew safety, financing conditions, or corporate risk limits. The result is a commercial constraint layered on top of a physical one: even without a formal blockade, the cost structure of Red Sea transit has changed enough to alter routing decisions.

Freight rates on Asia-Europe routes currently sit 25 to 40 percent above pre-crisis levels, according to market data. Asia to U.S. East Coast rates are running 15 to 25 percent higher, with 8 to 12 additional transit days added by Cape of Good Hope rerouting. Approximately 5 to 7 percent of global container capacity is being absorbed by longer routes, reducing the effective supply of shipping capacity available for normal trade. For mining operators, these elevated freight costs translate directly into higher delivered costs for inputs, compressing margins on operations that were already navigating elevated energy prices and tightening acid markets.

Stephen Sanders at Northeastern University has warned that coordinated closure of both major straits would produce a correlated global supply chain crisis, with higher energy prices, freight costs, inflation, and manufacturing delays reinforcing one another. The word correlated is important here. Supply chain models that treat disruptions as isolated events significantly underestimate the risk. When Hormuz and Bab el-Mandeb are disrupted simultaneously, the shock does not simply double. It amplifies, because the redundancy that normally allows shippers to route around one problem has been removed.

What the Policy Response Is Missing

GEM's core argument, both in September's chokepoint analysis and in its earlier work on chain fragility, is that governments and procurement teams are measuring the wrong things. Policy attention has been heavily concentrated on mine output and deposit ownership. The actual bottlenecks, as GEM puts it, sit in reagent tanks, furnaces, ports, laboratories, and equipment order books. Maritime chokepoints belong in that list.

The practical implication is that supply chain resilience programs need to be designed around disruption scenarios, not just resource inventories. GEM frames this directly: rather than asking who controls a resource, policymakers should ask how long industries can continue operating if a mine, refinery, shipping route, or supplier is disrupted. That is a fundamentally different question, and it produces different answers about where investment and contingency planning should be directed.

One specific gap is in the area of standardized risk disclosure. As I covered in my analysis of the ANSI workshop earlier this month, the United States lacks the coherent national framework for critical minerals traceability and supply chain transparency that the EU has built through its Critical Raw Materials Act. That standards gap makes it harder for procurement officers, investors, and regulators to identify chokepoint exposure at the portfolio level. A mine operator knows whether its sulfuric acid supply transits the Red Sea. An investor assessing a battery manufacturer's supply chain risk may have no visibility into that dependency at all.

The DRC provides a useful data point on where attention is currently directed. Congolese copper exports hit a record 1.72 million metric tons in the first half of 2026, with the share shipped to the United States and Europe doubling from 2025 levels as Kinshasa pushed to diversify away from Chinese buyers. That is a meaningful development in terms of supply diversification at the mine output level. But the copper still has to travel. If the shipping corridors it depends on are compromised, the diversification achieved at the extraction stage does not translate into resilience at the point of use.

What to Watch Next

The near-term trajectory at Bab el-Mandeb depends heavily on whether the Houthis press further toward Dhubab on the Yemeni mainland and whether Saudi Crown Prince Mohammed bin Salman's direct appeals to President Trump for U.S. military intervention produce a response. The Houthis' rapid advance has brought them to within roughly 32 kilometres of the U.S. military base in Djibouti. That proximity changes the calculus for American decision-makers in ways that purely commercial disruption does not.

On the commercial side, watch transit data from MarineTraffic and freight rate indices on Asia-Europe routes over the next two to three weeks. The previous Houthi campaign showed that traffic can collapse quickly once a critical mass of operators makes independent rerouting decisions. The psychological effect of the 2023-2024 episode was more durable than the operational disruption itself: rates and routing patterns did not fully normalize even after the attacks paused. A second disruption at the same chokepoint is likely to produce a faster and more persistent commercial response from shipping operators.

For critical mineral markets specifically, sulfuric acid availability and pricing will be the earliest indicator of stress. Latin American copper producers and Indonesian HPAL operations are the most exposed, and production guidance revisions from those quarters would signal that the chokepoint risk has moved from analysis into operational consequence. GEM's central scenario projects $1.37 billion in additional cost premiums across a 90-day disruption window. Whether the actual figure lands closer to the $480 million floor or the $2.48 billion ceiling will depend on how quickly inventories are drawn down, how aggressively insurers reprice Red Sea cover, and whether any diplomatic or military development changes the physical situation at the strait. None of those variables are currently moving in a reassuring direction.