Thanks for the query. I had a similar query just a few days ago on the same accident. I dont know if you and the person who emailed me are related, but here is what I found:
There were no fatalities on September 9, 1940 in West Virginia; however, on September 6, 1940, there was a dual fatality at the Pinnacle North mine. These are the two miners that were killed:
Carl Camaresi, 06-Sep-1940 Mercer County, Age-41, Experience-25years, Italian, Occ-Machine Runner, Mine-Pinnacle North, Company-American Coal Co., Causs-Slate Fall Married, 11 dependents, Cemetery-Woodlawn Cemetery Bluefield WV
Louis Funari, Mercer County, American Coal Co., Mine-Pinnacle North, Date-06-Sep-1940, Italian, Experience-12years, Age-45, Occupation-Machine Man, Married,5 dependents, Cause-Slate Fall, Buried-Woodlawn Cem, Bluefield WV
The accident report that this information came from is in the collection of the West Virginia State Archives in Charleston. The fine folks there can retrieve it and copy it for you, though I'm not sure of the current cost. (it depends on the size of the report, and I'm not sure what the per page fee is now. It used to not be too much).
Hope this helps - any thing else I can do, just let me know!
Mine Research Group