When iron ore is crushed and screened at the mine, it is split by size into two main products: lumps and fines. They come from the same ore, yet they follow very different paths into steel, and they are priced differently.
What counts as lumps and fines
Exact size ranges vary by mine and contract, but the broad split is:
- Lumps: coarser pieces, commonly from around 10 mm up to a few centimetres.
- Fines: material below roughly 10 mm, down to fine particles.
- Calibrated lump ore (CLO): a closely sized lump product, often used in sponge iron (direct reduced iron) kilns.
- Concentrate: very fine, high-grade material produced by beneficiation, usually destined for pellets.
Lumps: straight into the furnace
Blast furnaces and direct-reduction kilns need a permeable burden so hot gases can flow through the charge. Lumps provide that. Lump ore with good strength and chemistry can be charged directly, skipping an agglomeration step. This is why lumps usually command a premium.
India's large sponge iron industry, which uses coal-based rotary kilns, is a major consumer of calibrated lump ore and pellets.
Fines: sinter
Fines cannot be charged directly because they would choke the furnace. Most are sintered: mixed with fluxes and fine coke, then fired on a moving grate so particles fuse into a porous, strong cake that is broken and sized for the blast furnace.
Very fine material: pellets
Ultra-fine ores and concentrates are too fine even for sintering. They are rolled with a binder into pellets of uniform size and fired. Pellets are strong, consistent and well suited to both blast furnaces and direct-reduction plants. Magnetite concentrate is especially suited to pelletising. See hematite vs magnetite.
Comparing the products
| Product | Typical route | What buyers check |
|---|---|---|
| Lumps / CLO | Blast furnace, DRI kiln | Fe, silica, alumina, strength, size range |
| Fines | Sinter plant | Fe, silica, alumina, LOI, size distribution |
| Concentrate | Pellet plant | Fe, silica, fineness, moisture |
Why fines are generated
Every handling step breaks some lumps into fines: blasting, crushing, loading, transport and unloading. Friable ores generate more. Contracts usually allow a percentage of undersize in lump deliveries, and good handling keeps it within that limit.
Minequor's iron ore division
Our upcoming iron ore division is developing three belts in Goa, Odisha and Karnataka, covering hematite and magnetite ores as lumps and fines. See the iron ore page for updates and to register interest.