Well, I'd dug the hole a while ago, thinking I was going to build a firebox down there for an outdoor boiler system, but then the compost bug hit me again, and I decided to take a detour into this experiment. Here's a blurry photo of the hole, with some redwood branches criss-crossed on the bottom and old chicken wire over that, for bottom aeration.
Again, the hole, now with a half a truckload of woodchips in it, and a very ornery twisting of 1inch diameter black poly water pipe that I found on my new property. Believe me, organizing that into a coil was much more work than you imagine it.
Then came the 3 truckloads of woodchips from the next property over, layered with two truckloads of horse manure from down by town, all capped with about 4 wheelbarrows of leaves/forest floor duff that I had gathered as fire prevention last autumn. And each layer got gooey veg oil filter leavings as well as a bit of green leaves. Ready to start cooking!
Then, we left for a bit, and so didn't start the experiment. Getting back, I opened the water valves to have the water start flowing through.... and, I could hear a leak. yay. So, I had to dig out a bunch of that moist, smelly compost to find the leak, repair it and put it all back together. I needed the exercise anyway! It's all back together again, so we'll see how she does!