About 400 people attended the lecture
Former NUM leader Arthur Scargill has paid tribute to the two miners who died during the pit strikes 25 years ago.
David Gareth Jones, from Wakefield, died amid violent scenes outside Ollerton colliery in Nottinghamshire on 15 March 1984.
On 15 June Joe Green was crushed to death by a lorry while picketing in Ferrybridge, West Yorkshire.
At a memorial lecture in Barnsley, Mr Scargill said the men paid the "ultimate price" for their cause.
Wreaths were laid at a memorial for Mr Jones and Mr Green outside the Miners' Hall in Victoria Road, Barnsley.
About 400 then packed the hall to listen to Mr Scargill.
He told them the late miners had died for "one of the noblest causes that this class has ever known".
He said: "Twenty-five years after 1984 we remember David Gareth Jones and Joe Green.
Mr Scargill said Mr Jones and Mr Green would not be forgotten
"David Jones was at the beginning of his life, a young man with everything to look forward to.
"When I visited his family I hardly knew what to say. How do you speak to a mother and father whose son has just been killed?
"Over 15,000 Yorkshire miners and miners from all over Britain came to the funerals of both David Jones and Joe Green.
"All those lads on strike, all those lads were friends of David and Joe and they live on in our hearts, in our memories and in our history as martyrs of this movement who gave and paid the ultimate price.
"We'll never forget them."