I am seeking information about my great-grandfather David Colin Campbell an American mining engineer who, prior to WWI, participated in the development of explosives for the English government. He subsequently enlisted in the AEF / Army and served under General Pershing and Patton in the 304th Tank Corps.

I believe that he may have worked with your group.

I would like copies of any documents / photos (proofs) as well as information about any English memoirs of that time.

Please advise if any costs - I am near Buffalo, NY USA - we can use email rather than snail mail.

Many thanks for your time & attention!