Jeff Shaara touches on this in his novel "Last Full Measure". Granted, this is from a novel, but, like his dad before him, he tries to base everything on historical fact. His account of the Overland campaign is gruesome. Grant was suffering such high casualty rates -- and the political cost of calling up more men was too high -- so Grant had to clear the cupboards of other areas, especially fortified areas, to replenish his ranks. Apparently, a lot of these heavy artillery men got little or no infantry training and were thrown into their first action at Cold Harbor. Their casualty rates from that fight were horrific. Brave men, unprepared and poorly led. I urge you to pick up that novel if only for his depiction of Cold Harbor. Grant was too confident, thought Lee was battered worse than he actually was. (He made Lee's mistake at Gettysburg.)
Shaara's depiction of The Crater is also first rate. As he tells it, the union plan was brilliant and it gave Lee a genuine cardiac moment, and only poor coordination and last minute changes of the Union plan doomed it.