I worked on a few of that one's little brothers overt he years. From little M15, M30, M35, M50 and the biggest the M-65's!
Back in those days the company that owned the quarry also owned a Mack dealership in Easton Pa. so the majority of the truck the used for many years were Macks of one kind or another. A lot of B models from B-42's right up to B-81's then DM and R models one F model and a couple Superliners. Some were over the road trucks but most off-highway.
Probably the biggest job was repairing a M-65 that did an end over flip loaded into a ditch. Don't recall if the same driver drove it after that accident. Was not exactly his fault as the truck had a failed retarder hose that burst just as he left the loading face to start down a steep road with a 90ºleft turn at the bottom and the Hough 400 loader was not fast enough to catch him and a lot of the equipment back then did not have CB radios.
Lucky they had strict seat belt rules so after they took him to the ER and everything checked out OK other than minor bruising I guess another driver and him spent some time with some self medication at a local bar.