Friday:
Hilary A. Herbert was promoted to
colonel of the 8th Regiment, Alabama Infantry. In 1893, President Grover Cleveland appointed him Secretary of the Navy.
Sources: wikipedia article, "Hilary A. Herbert"
http://bioguide.congress.gov/scripts/biodisplay.pl?index=h000524
Bonus: Closest I could come was
Leonidas Polk. The facts I found don't fit the question exactly, but I can't find anything closer. On Nov. 11, 1861, while he was observing a firing of the "Lady Polk," named for his wife, the cannon exploded, killing 10 of the crew of 13 [18 were killed per another source, and 11 per yet another source] stunning Polk and blowing his clothes off. June 13, 1864, Polk was killed by a Union artillery shell. However, the shell was aimed; Sherman had spotted the group of generals (Polk, Johnston, Hardee) 600 yards (0.34 miles, so "over a quarter mile") away on Pine Mountain and ordered that they be fired upon. The others scattered, but Polk didn't leave quickly enough.
Sources:
wikipedia article, "Leonidas Polk."
http://civilwartalk.com/threads/10-dahlgren-gun-explosion-why.73115/ (which led me to Polk)
http://hubpages.com/education/Big-Guns-of-The-American-Civil-War (the "Lady Polk" explosion)
wikipedia article, "Columbus-Belmont State Park" states that 18 soldiers were killed in Lady Polk explosion
http://www.t-g.com/story/1201416.html (says 11 were killed)
http://www.historynet.com/leonidas-polk-southern-civil-war-general.htm (death)
This has been interesting, especially the varying sources. I'm looking forward to seeing if Polk is the real answer!