West Cumbria Hematite Mines
West Cumbria hematite mines at Frizington, Cleator Moor and Egremont: kidney ore, specularite crystals, streak, and British Geological Survey closure dates.
The West Cumbria hematite mines worked haematite that replaced Carboniferous limestone in a belt from Lamplugh to Calder Bridge, around Frizington, Cleator Moor and Egremont. West Cumbria is known for kidney ore, hematite of hardness 5 to 6. Large-scale mining in West Cumbria ended in the late 1970s, according to the British Geological Survey.
In short
- The orefield. The British Geological Survey describes a narrow belt between Lamplugh and Calder Bridge, in two unequal parts. The exposed part lies north of Egremont, where Carboniferous limestone crops out. The concealed part runs south of Egremont under Permo-Triassic strata. The main centres were Frizington, Cleator Moor and Egremont.
- Kidney ore. The BGS says the deposits are almost exclusively haematite, and the area is famous for the fibrous mammillated variety called kidney ore. Its conical broken fragments are called pencil ore. The Handbook of Mineralogy hematite sheet names Cleator Moor and lists radiating fibrous, reniform, botryoidal among its habits.
- The streak rule. Kidney-shaped iron oxides are not all hematite. The hematite sheet gives a cherry-red or reddish brown streak, goethite brownish yellow and magnetite black. A 20 g piece weighs 16.20 g in water if hematite and 16.14 g if magnetite, so the balance cannot tell them apart; the streak can.
- End of mining. The BGS says large-scale mining in west Cumbria ended in the late 1970s with the closure of the combined Beckermet–Florence Mine at Egremont. Small-scale working at Florence Mine continued until 2006 on one BGS page and until the late 2000s on another. We print both.
- Worked iron content: pure hematite, Fe2O3, is 69.94% iron by mass. The BGS gives 50 to 60 per cent iron for Cumbrian ore. If the gangue carried no iron, that would be 71.5% to 85.8% hematite; the sources do not give the mineral proportions.
| Species | Formula (Handbook) | Hardness | Density | Streak (sheet) | 20 g piece in water | Sheet names the West Cumbria field? |
|---|---|---|---|---|---|---|
| Hematite | α-Fe2O3 | 5–6 | 5.26 | Cherry-red or reddish brown | 16.20 g | Yes: Cleator Moor |
| Goethite | α-Fe3+O(OH) | 5–5.5 | 4.28 | Brownish yellow, yellow-orange, ocher-yellow | 15.33 g | No |
| Magnetite | Fe2+Fe3+2O4 (IMA; not printed on the sheet text) | 5.5–6.5 | 5.175 | Black | 16.14 g | No |
| Baryte (sheet: barite) | BaSO4 | 3–3.5 | 4.50 | White | 15.56 g | Yes: Frizington, Cleator Moor |
| Calcite | CaCO3 | 3 | 2.7102 | White | 12.62 g | Yes: Egremont, Frizington |
| Aragonite | CaCO3 | 3.5–4 | 2.95 | White | 13.22 g | Yes: Frizington, Cleator Moor |
| Dolomite | CaMg(CO3)2 | 3.5–4 | 2.86 | White | 13.01 g | Yes: Frizington |
| Manganite | Mn3+O(OH) | 4 | 4.29–4.34 | Reddish brown to nearly black | — | Yes: Egremont |
| Hausmannite | Mn2+Mn3+2O4 | 5.5 | 4.84 | Dark reddish brown | — | Yes: Wyndham Pit, near Egremont |
Where the West Cumbria orefield is
The belt. The British Geological Survey (British regional geology: Northern England, 2010, on its Earthwise site) places the west Cumbrian iron orefield in a comparatively narrow belt between Lamplugh and Calder Bridge. The BGS says haematite was no doubt first discovered in the exposed part north of Egremont. The concealed southern part runs beneath the unconformable Permo-Triassic cover. Frizington, Cleator Moor and Egremont were the main centres of operation.
How the ore lies. The deposits are large irregular or flat-lying replacements of limestone, usually next to faults. Bedding, stylolites and fossils of the original limestone are often preserved in the haematite, while mudstone interbeds can run through the ore unreplaced. Haematite also replaces limestone-rich parts of the Brockram at the base of the Permo-Triassic. The BGS cross-sections show the Florence and Ullcoats mines and the Bigrigg mine, all at Egremont.
How it formed, as far as anyone knows. In the most widely accepted models, the BGS says, iron-rich fluids were driven up-dip into the limestones along faults, from Permo-Triassic sediments of the Irish Sea Basin or from the western Lake District granites. Fluid inclusions point to hypersaline brines at up to 120 °C. The age is still disputed: Permian or Early Triassic, or post-Triassic. The other English localities, including Caldbeck Fells and Alston Moor, are on the localities index.
Kidney ore, pencil ore and specularite
Three forms, one mineral. The BGS says compact, massive haematite is the most abundant form. The area is famous for the fibrous mammillated variety known as kidney ore, and its conical broken fragments are termed pencil ore. Crystallised haematite, specularite, is present locally in small quantities. Its photograph of a large kidney-ore mass was taken in the Lonely Hearts Orebody at Florence Mine, Egremont; the hammer head in it is 17 cm long.
What the sheet adds. The Handbook hematite sheet lists radiating fibrous, reniform, botryoidal or stalactitic masses among its habits. That matches kidney ore’s smooth outside and radiating inside. It gives H 5–6 and D 5.26, steel-grey to red, with a cherry-red or reddish brown streak. For the shape word, see what does botryoidal mean; the species page is hematite.
Spelling. The BGS writes haematite, as older British labels do. The IMA list writes hematite, Fe2O3. They are the same species.
Is it hematite? The streak rule for kidney-shaped iron ore
Shape is not enough. The goethite sheet also lists reniform, botryoidal, or stalactitic masses, and goethite can be banded. Magnetite is the other dark, heavy iron oxide. The table above gives the three on the sheets’ own numbers.
The decision rule. Rub an inconspicuous corner on unglazed porcelain. Cherry-red or reddish brown is consistent with hematite. Brownish yellow to ochre points to goethite. Black points to magnetite, which the magnetite sheet also records as strongly magnetic; the hematite sheet records no magnetism. See how to use a streak plate and which minerals are magnetic.
Where the balance fails. Weighed in water, a 20.00 g piece reads 16.20 g as hematite (D 5.26) and 16.14 g as magnetite (D 5.175). That is 0.06 g apart, inside the error of a kitchen balance. Goethite at 15.33 g is further off, but a porous kidney is rarely pure. The method is on how to measure specific gravity at home.
Which minerals the Handbook places in the West Cumbria field
Seven sheets. Method: a script reads the Distribution field (from Distribution: to the next Name:) of each sheet named here, as pdftotext -layout text, strips diacritics, expands ligatures, joins line breaks and matches case-insensitively. Among the sheets fetched for this page, seven name a place in the west Cumbrian field: hematite (Cleator Moor), baryte (Frizington and Cleator Moor), aragonite (Frizington and Cleator Moor), calcite (Egremont and Frizington), dolomite (Frizington), manganite (Egremont) and hausmannite (the Wyndham Pit, near Egremont). The BGS says manganese oxides accompany the haematite locally and were worked on a small scale in the Bigrigg and Askham areas.
Excluded Cumbria matches. The same search also hits Cumbria on sheets that mean other orefields: Alston Moor (galena, sphalerite), Caldbeck Fells (hemimorphite, langite, plancheite, pseudomalachite, rosasite and others) and Keswick (childrenite). Those are not the hematite field and are not counted here.
Documented negatives. The BGS lists siderite and fluorite in the gangue, but the siderite and fluorite sheets we fetched do not name the west Cumbrian field. They are left out of the table for that reason. Calcite and aragonite are the same composition; see is aragonite the same as calcite. The species index has the species pages.
1968, the late 1970s, 2006: when mining ended
The long view. The BGS says it is highly probable that haematite was worked for iron in Cumbria in pre-Roman times, with the first documents from the 12th century. Production peaked in the 19th century. Large-scale mining ended in south Cumbria in 1968 and in west Cumbria in the late 1970s. A second BGS page puts that end at the closure of the combined Beckermet–Florence Mine at Egremont. It estimates about 250 million tonnes of haematite ore raised in Cumbria since the mid 19th century, west and south together.
Florence Mine after that. One BGS page says small-scale production for pigment continued until 2006 from shallow underground workings at Florence Mine, Egremont. The other says until the late 2000s, for specialised steel making and pigment. We print both and do not pick one. We say nothing about the mine’s present state or about access.
The Florence trap. A BGS pigment survey lists another Florence Mine, in Devon near North Molton, which yielded spathic ore and haematite. “Florence Mine, haematite” on an old label is not enough. Write Florence Mine, Egremont, Cumbria, England, or the town for the other mines; see how to label and catalogue a mineral collection. Nothing here is offered for sale; the wanted list is the only commercial route.