But the alternative -- the practice of breaking off old bolts , patching the hole and drilling a new one nearby -- weakens the rock face and mars its appearance .
To do that , he said , you really have to be committed to sustainable bolting .
The alternative -- the practice of breaking off old bolts , patching the hole and drilling a new one nearby -- weakens the rock face and mars its appearance .
To do that , he said , you really have to be committed to sustainable bolting .