You are most likely to get a plausible response from a World War One website such as _www.westernfrontassociation.com_ (http://www.westernfrontassociation.com) . Meanwhile understand that several countries as the war advanced released service men for work in strategic industries. In Great Britain, these included coal mining. Skilled workers were often exempted from military service altogether if they continued to work in their specialties. LGS