Mining iron ore is a large-scale industrial process that moves millions of tons of rock each year. It starts with finding a deposit, then removing the earth above it, blasting the ore loose, hauling it out, and crushing and processing it into a product steel mills can use. Australia and Brazil together supply nearly 78% of the world’s seaborne iron ore, and the vast majority comes from open-pit surface mines rather than underground operations.
Finding the Ore
Before any digging begins, geologists need to confirm that a deposit exists, estimate its size, and determine whether the iron content is high enough to justify the cost of extraction. Iron ore is graded by the percentage of iron (Fe) it contains. High-grade ore sits around 65% Fe, medium-grade ore around 62% Fe, and low-grade ore falls below 58% Fe. The grade matters because it determines how much processing the ore needs before it can be sold, and lower grades mean higher processing costs.
Two main geophysical survey methods help locate deposits. Aeromagnetic surveys measure distortions in Earth’s magnetic field caused by iron-rich rock below the surface. Gravity surveys detect dense ore bodies by measuring tiny variations in gravitational pull. Gravity methods were originally used to find non-magnetic ores, but they’ve become broadly useful for mapping both magnetic ores and the regional geological structures that tend to host iron deposits. Once surveys narrow down a target area, drilling programs pull up core samples to confirm the ore grade and depth.
Open-Pit vs. Underground Mining
Open-pit mining accounts for the majority of global iron ore production. It works best when ore bodies are relatively close to the surface and spread over a wide area. The mine is carved into terraced benches that spiral downward, giving trucks a ramp to drive in and out.
Underground mining is reserved for deposits buried too deep for an open pit to reach economically. These tend to be lower-grade ore bodies where the cost of removing all the rock above them would be prohibitive. Underground iron mines exist but are far less common, and the per-ton extraction cost is significantly higher because of the need for tunneling, ventilation, and more complex logistics.
The Extraction Sequence
Once a surface mine is established, extraction follows a repeating cycle of six steps: drilling, blasting, loading, hauling, crushing, and screening.
First, the soil and overlying rock (called overburden) are stripped away to expose the ore. Workers then drill holes into the ore body in a precise pattern. These holes are packed with explosive mixtures and detonated. Blasting fractures the rock into pieces small enough for equipment to handle.
After blasting, massive electric shovels, hydraulic excavators, or front-end loaders scoop up the broken ore and dump it into haul trucks. The largest mining trucks on the market, like the Caterpillar 797F, carry payloads of 400 tons (363 metric tons) per load. These trucks transport the ore from the blast site to the primary crusher, where the rock is broken down further. From there, it passes through screening equipment that sorts pieces by size, sending oversized chunks back for more crushing and correctly sized material on to the processing plant.
The Two Main Ore Types
Iron ore comes primarily in two mineral forms, and each requires a different processing approach.
Hematite is the more desirable of the two. It tends to occur at higher grades and is easier to process. High-grade hematite can sometimes be crushed, screened, and shipped directly to steel mills with minimal additional treatment. Lower-grade hematite, however, requires more complex separation techniques.
Magnetite ore is naturally magnetic but generally lower in iron content. It needs more energy-intensive processing to reach a sellable grade. The upside is that its magnetic properties make separation straightforward: when crushed magnetite is passed through a magnetic separator, iron-rich particles cling to the magnets while waste rock falls away.
Turning Raw Ore Into a Usable Product
Most iron ore mined today isn’t pure enough to go straight into a blast furnace. Beneficiation is the umbrella term for the techniques that raise the iron content and remove impurities like silica, alumina, and phosphorus.
For magnetite, wet low-intensity magnetic separation is the standard method. The crushed ore is mixed with water and passed through magnetic fields. Iron particles stick; everything else washes through. This process can produce concentrates with iron grades above 65%.
Hematite is trickier because it’s only weakly magnetic. Processors use three main approaches, often in combination. Gravity separation exploits the density difference between iron minerals and lighter waste rock, using spiral concentrators, hydrocyclones, or jigs to sort particles. Flotation uses chemical reagents to make either the iron or the silica selectively attach to air bubbles, which float to the surface and get skimmed off. In one common flotation setup, starch-based compounds (corn starch, tapioca starch, or dextrin) coat the iron particles to keep them from floating, while an amine-based collector attaches to silica grains and carries them to the surface for removal.
A more advanced technique for very low-grade hematite involves magnetizing roast. The ore is heated in a controlled atmosphere that converts hematite into magnetite, after which standard magnetic separation can be used. One study achieved a concentrate grade of 65.25% Fe with a recovery rate of 72.5% using this method.
Where Iron Ore Comes From
Iron mining is concentrated in a handful of countries with massive, high-quality deposits. In 2025, Australia dominates seaborne supply with roughly 696 million metric tons of exports, accounting for nearly 56% of the global total. Brazil follows at 277 million metric tons (about 22%). Canada, South Africa, and India round out the top five, but together they contribute less than 9% of seaborne supply.
Australia’s Pilbara region in Western Australia is the epicenter of global iron mining. It hosts operations run by BHP, Rio Tinto, and Fortescue, producing well-known ore brands like Pilbara Blend Fines and Newman High Grade Fines. Brazil’s output comes largely from the Carajás and Minas Gerais regions, producing Brazilian Blend Fines and other medium- to high-grade products.
Autonomous Trucks and Modern Operations
Iron mining has become one of the most automated sectors in the mining industry. Over 1,000 autonomous haul trucks now operate globally, with Australia leading the way at 706 trucks across 25 mine sites. Canada follows with 177 autonomous trucks.
The three largest operators of autonomous fleets are all major iron ore producers. BHP runs about 300 autonomous trucks, including a fully autonomous fleet of 42 ultra-class haul trucks at its South Flank iron ore mine in the Pilbara. Fortescue operates 193, and Rio Tinto runs 187. These driverless trucks follow pre-programmed routes 24 hours a day, reducing fuel consumption, tire wear, and the safety risks that come with human operators driving 400-ton vehicles on steep pit roads.
High-Grade Ore and Green Steel
The quality of iron ore a mine produces increasingly determines its market value, and the gap between high-grade and low-grade ore is widening. Steel producers shifting toward direct reduction (a process that uses natural gas or hydrogen instead of coal) need ore with at least 65.5% to 68% Fe. Direct reduced iron made from this ore contains 86% to 93.5% total iron by weight, with very low sulfur and phosphorus levels.
This demand for premium ore is reshaping which deposits get developed. Mines producing ore below 60% Fe face growing pressure, as their product requires expensive additional processing before it meets the specifications of newer, lower-emission steelmaking routes. For mining companies, the message is clear: the cleaner the ore coming out of the ground, the more valuable it becomes.