With the gas line moved and safely buried, I can now start filling in the trench over the new gas line. The main source of that fill is the dirt being excavated to allow me to run the wall from where it currently ends to the street.
The "dirt" in the front of the yard, near the light pole, is mostly ground up limestone mixed with a lot of rock. We pull the rock out, and mix in leaves and grass to try to improve the quality of the soil, but even then, it is going at the very bottom of the trench. At least it should improve drainage.
A couple of days of digging, and we have it ready to pour the concrete base to put the stones on top of.
In this situation, we will not take the wall all the way down to bedrock. It's not clear how far that is, since all of this soil was torn up for the street and utilities. Plus we only need the wall as a base for the limestone blocks on the top. And we need to keep the cement well away from the gas line for the neighbors that runs up close to where the first part of the wall stops. We have some re-bar from the excavations back closer to the house, and will reuse it in this part of the wall to make it work a bit better.
Two days of framing it up and pouring concrete,
and we have the base ready for the limestone blocks. The concrete calculator said we would need 18 bags of concrete mix for a wall 10 feet long, 30 inches high and 4 inches deep. We ended up needing 20.5 bags.
The gas company people had said to be very careful not to get concrete on the gas line for the neighbors, so we framed out a hole for them, filling it with 60 pounds of sand.
Once the concrete wall is poured, and set, we can mortar the limestone blocks along the top of it, trying to match the height and straight-ness of the previous set. This takes another day of work.
You can see the "hole" that we left in the concrete wall around the neighbor's gas line (which you can't see, since it is buried in sand.
Next, we dig out all the way to the curb, the full width of the trench, extract the rock, mix the dirt with leaves and use it to fill part of the trench.