As I stated earlier... I am not arguing the fact that an excavator is a great piece of iron. My major malfunction with this thread is people expecting trade loaders to do things they aren't made to do.
If I may ask about your water/sewer work, or trench work... what scale are you working on? I know this is where I come off sounding like a jerk but I don't think you and I are on the same page. As for your drying dirt problems.... the site we just finished was beyond your worst nightmare. Silty material coming out of the ground at 30+ percent moisture.. optimum of 16% and we're generating dirt at an excessive rate. Lets just dry it out right? Well we had no room to spread it. By tossing in wet lifts we literally doubled the area we had to dry it if you get my drift.
Trench boxes? Yeah we don't use those much up here... why? Speed. Hard to drag a box 25ft deep thats gonna allow you to lower in pipe with a PC600. I'll load up some pics for ya... you'll see why the 973 is our ace in the hole when it comes to backfill.
I don't do much new development work as everyone bids on that type of work. No money in it. So why do it??
I work mostly in replacement work or splitting storm/sewer pipes. Cuts down on the number of people able to do that type of work. Most people hate or can not dig/lay around all kinds of utilities. I love that kind of work. Some days its hard to see the bottom of the trench with all the different pipes, wires and other utilities.
Most jobs We have to use trench boxes as there is not room to slope the side out on. Also I don't want to dig that big of trench. Faster to just pull a trench box along. Lot less dirt to move.
I lay about every size pipe there is but 72'' to 84'' is the most common. The biggest I have layed is 120"" pipe. Seems like engineers will split the flow if the pipe requirement get much over 96" I don't own a 600 size machine, but I have a good friend that has one and I will rent/swap him when I need one. Works out good for both. As far as depth of bury it varies greatly. 20 to 25 foot would be an average. I have had to step down and still use a long reach to get to the depth I needed, but the does not happen often. A lot of the old parts of towns are built in hills and the cities do not want to install pumping stations if the don't have to. So I just trench trough the hill.
Sounds like We have silt clay soil probably like you do. It is a dream to work in compared to the sugar clay or gumbo that is around here. If that was all I had to work with I would probably do things different. But with the soils I have to work with, When either gets much above 25% they will run like water. The more you work the sugar clay the worse it gets. You have to get to the grade you want get what needs to be done and get the dirt back in fast before it really turns bad. The more you move it the worse it gets. Gumbo goes from wet to as hard as concrete just over noon. When that happens you are in trouble trying to back fill right as all you have is chunks to work with.