Cave was born in Edlington in Yorkshire and grew up in nearby Brodsworth. He became a coal miner on leaving school, and quickly became active in the National Union of Mineworkers (NUM). As a committed socialist, he became a key ally of Arthur Scargill, then a member of the branch committee at a nearby pit.
Cave rose through the ranks of the NUM, becoming the Brodsworth pit's delegate, then gaining election to the executive of the Yorkshire Area and, in 1982, becoming Agent for the Yorkshire Area, then a full-time post. Yorkshire was the largest area of the NUM, so he played a key role during the strike of 1984/5.
In 1990, Cave was elected as Vice President of the NUM, but the national programme of pit closures had reduced the importance of this role, and Cave had time to devote to other political activities. In particular, he was a strong support of Fidel Castro, and arranged aid convoys to Cuba, as a result of which he travelled to the country and met Castro. He also joined Scargill's Socialist Labour Party, and was elected as its President in 1997, serving until his death in 2002. In this role, he stood on the party list in the 1999 European Parliament election in Yorkshire and the Humber, but was not elected.
Scargill and Cave were removed as trustees of the Yorkshire Miners' Welfare Trust Fund Scheme and the Yorkshire Miners' Welfare Convalescent Homes in 1997, after the High Court found that they had ignored rules on the transfer of funds, in an attempt to avoid them becoming subject to partnership funding schemes, which they opposed. The Court agreed that the two had not attempted to profit from this transfer.
- Martin Wainwright, "Obituary: Frank Cave", The Guardian, 17 January 2002
- "1999 Election candidates; Yorkshire and the Humber". UK Office of the European Parliament. Archived from the original on 28 August 2009. Retrieved 4 June 2009.
- "1999 Election Results: Yorkshire and Humber". UK Office of the European Parliament. Archived from the original on 15 June 2011. Retrieved 5 June 2009.
- "Scargill 'mismanaged' charities", BBC News, 22 December 1997