In the early days of the industrial revolution, iron-making furnaces were usually established at locations where iron ore, known as Clay Band and Black Band iron ore occurred with coal measures, providing two vital ingredients for the furnaces. National examples were Glasgow, Birmingham and South Wales. More locally, iron-making companies were founded near Stanton-by-Dale, and also at Staveley, both in the Derbyshire coal field.
There are several other types of iron ore from the group of ‘stratified’ iron ores, that occur in different areas of the country:
* Frodingham Ironstone from the Lower Lias of the Jurassic Period, that is found to the east of Scunthorpe.
* Cleveland Ironstone is found mainly in an area of some 50 square miles south-east of Middlesborough, and is of a similar age to...
* Marlstone iron ore which is discussed below.
* Weald Ironstone, found as a Clay Band type of deposit in the Weald of Sussex and Kent. This ore supported iron making in this location, which became the centre of the industry during medieval times.
* Claxby Ironstone is found in an outcrop running for about 15 miles to the south from Caister in Lincolnshire.
Haematite Iron Ore is quite different in both its formation and appearance. It did not occur when strata of rock were laid down, but was a replacement deposit that occurred later, and is therefore known as an ‘unstratified’ ore. The ore is rich in iron and has a low phosphorus content, and occurs as veins, or irregular shaped bodies. It is found in Cumberland, Furness, and also further south in the Glamorgan and Forest of Dean areas.
The form of ore worked locally is found in the Marlstone rock bed, along the ridge from the Wartnaby area in a north-easterly direction towards Grantham. Also found locally is Northampton Sand Ironstone, which occurs along the line of the Oolitic Cliff (on which Waltham-on-the-Wolds stands) that runs from near the Humber estuary to the Corby area, and this ore is found in areas to the south-east of the line of the cliff.
The areas tinted yellow show the general extent of the Marlstone outcrop between the top of the Marlstone Cliff that rises some 250 feet from the Vale of Belvoir, to the foot of the Oolitic Cliff.
Marlstone is a form of limestone, but weathering and chemical changes over the ages have replaced the lime with hydrated oxides of iron, and become a viable iron ore. The seams of ore occur to varying depth from the top of the Marlstone bed, but the change in colour between the iron rich ore and the non-iron bearing Marlstone below is usually well defined. The ore occurs to a varying degree across the local Marlstone outcrop, and workable seams were typically from eight to twelve feet deep. The seams can taper off to nothing into areas known as ‘washouts’, where the iron enrichment of the stone has not occurred. Where enrichment is to a higher degree the iron ore is a rich brown colour and known as ‘soft’; where the enrichment is less so, the ore is known as ‘limey’.
The Ice Age affected the area by cutting valleys through the rock and also depositing large amounts of Boulder Clay over the rock formations and filling old valleys. There are also areas where the Marlstone has been completely eroded away, e.g. between the Holwell area and the Eastwell area; also in the deep valley known as the Knipton Bowl. Where valleys occur in the landscape the ironstone is on the high ground, a good example being Beastalls Quarries near Eaton village, where the quarry followed fingers of high ground between a number of small valleys.
The initial quarries opened where the ironstone was found near the surface, but as these areas became exhausted and quarrying moved on, the overburden tended to increase as the strata dips at between one to four degrees in a general easterly to south-easterly direction.
This sketch shows a section through the landscape from Stathern village, through Eaton village to the Oolitic Cliff. The distance scale is compressed in relation to the height scale to emphasise the Marlstone and Oolitic Cliffs, but this has the effect of increasing the angle of the dip in the strata, which in reality is much less than shown. The outcrop from the top of the Marlstone Cliff can be seen covering a distance of just under two miles, before disappearing under the later geological strata.
The Northampton Sand bed was quarried in the early 1880s by the Staveley Coal & Iron Co., and also Holwell Iron Co., in the area adjacent to the Melton to Grantham road in the vicinity of Waltham Station. However, the ore proved to be poor quality, and these two quarries were abandoned by the mid-1880s. Incidently, there was also a limestone quarry in the Lincolnshire Limestone bed near Waltham village. During World War II, Harlaxton Quarries were opened up to extract Northampton Sand iron ore from the area on the top of the ridge overlooking Harlaxton village; these continued working until 1974.