http://www.interpretermag.com/ukraine-liveblog-day-85-the-siege-of-slavyansk-continues/#2761 speaks of a bridge near the village of Dmitrovka and 'the outskirts of Oktyabrskoye'.
In a video in http://www.rferl.org/media/video/25384432.html a resident talks about a dam.
There are two bridges and dams in this area. The second one being the more probable location.
That road leads more directly to a known base of the Ukranian army.
Also look at the updated interactive map on http://ukraineatwar.blogspot.nl/2014/05/slovyansk-is-center-of-pro-russian.html
A video about the attack:
The light artillery/ammunition truck that did not get through to the Ukrainian position high over Sloviansk. Tuesday pic.twitter.com/NMyxd04Dtq
— Daniel Sandford (@BBCDanielS) 16 mei 2014