The collection consists of records of the Guest Keen Nettlefold group and predecessor companies, Glamorgan Hematite Iron Ore Mine Company and Cardiff Hematite Iron Ore Company. The records relate largely to Glamorgan Hematite Iron Ore Mine, Llanharry, but also include material from other significant iron and steel works in south Wales (Dowlais/East Moors, Briton Ferry works etc).
The deposit includes books of accounts, sale contracts books, annual account and wage records, geological and property records, records relating to personnel matters (accidents, pensions), output records, subject files from departments (including files kept by the works’ agent and manager) and blast furnace operating records. Other records concern geology, property and environmental issues, such as the alleged pollution of the River Ely, 1925-1930. The collection also includes some papers of iron ore mines in other parts of the UK (such as New Dunn, Gloucestershire) which were opened during the Second World War under the aegis of the Home Ore Department of the Ministry of Supply and managed by Glamorgan Hematite Iron Ore Company from their office in Cardiff under agency agreements.