One year ago tonight, mine rescuers discovered the remains of the last four missing coal miners deep inside Massey Energy's Upper Big Branch mine in West Virginia.

There had been hope that the four had made it to refuge chambers and were still alive. Optimistic rescuers carried four sets of breathing apparatus with them, hoping they would be used to bring the miners safely to the surface. The bodies of 25 other miners were found four days earlier.

A year later, the nation's worst coal mine accident in 40 years is still not fully explained. And the scope of the disaster still alarms mine safety experts.

Earlier this week, I joined a bus tour organized to bring community leaders from Grand Rapids to visit Detroit. One of the many cool places we visited that hasn’t made it into my writing so far is Earthworks Urban Farm. I didn’t want to overlook it – so here’s the second installation of what Detroit can teach other cities in Michigan about urban farming.