I checked the book Fatalities in the Coal Mines of Indian Territory & Southeastern Oklahoma, 1885-1962, and found no accident listed for John Christopher Britton. I also checked my mining accident databases for MO, KS, OH and PA and found nothing.
Perhaps you can find help on these web sites: http://www.linkpendium.com/https://beta.familysearch.org/
“LDS Family Search” If you place your browser on the name on the left, more information comes up. http://www.findagrave.com/ http://www.deathindexes.com/ http://search.ancestry.com/search/db.aspx?dbid=70734
“Billion Graves.com Burial Index”http://billiongraves.com/pages/search/
“Mining Accidents U.S., Canada, New Zealand and Australia”