Thomas began his career in the longwall industry in 1957 Working for British Coal in South Wales. He was with British Coal for 23 years and held various positions, including mine electrician, technical assistant, deputy mine electrical engineer and mine engineer.

In 1980 Thomas and his family, Marian, Neil and Paul, moved stateside when Dave took the position of master longwall mechanic at Jim Walters Resources. After four years there he joined the team at Island Creek Coal as manager of maintenance where he recommended, selected and supervised the application of new equipment for the Virginia Division.

When Island Creek was purchased by Consol Energy, he began working as a senior electrical engineer. From there Thomas joined Long Airdox as a project development engineer and in 1998 joined the team at Longwall Associates in their sales department.

During a special recognition presentation at Longwall Associates annual company picnic, Tony Campbell delivered the following farewell, "Your years of service to this company are priceless and your knowledge of the industry boundless. It is with gratitude that we all say thank you, Dave Thomas, for your years as a member of the Longwall Associates team. We wish you nothing but the very best".

The Longwall Associates contact for Thomas' sales and service accounts is Nelson Addair.