Friday, July 5, 2013

Water supply trenching

I had the site to myself today, a rare thing for a Friday of late. Nenad the electrician had an accident with a switchboard during the week which caused him a flash burn, so he's taken the time off to recover. Savva the plumber was due on site to install guttering and downpipes, but I may have forgotten to order them earlier in the week...

I have two main jobs to go on with, besides the electrical and plumbing work:

  1. Build the other set of garage doors, and finish the cladding fixture of the set I've already hung; and
  2. Dig the ~120m or so of trench up to the site of the header tank at the top of the hill.
With the weather forecast threatening rain all weekend and today remaining dry, I went with option #2 and fired up the bobcat.

After I gave it some more hydraulic oil, that is. This thing bleeds oil at rather an alarming rate, primarily because there's a hose in the bowels of the machine which is impossible to get at and leaks "a bit". This is part of the control plumbing, and so with all the driving around I did with it last week to shift trench gravel, it went through rather a lot of oil. I filled it before we began last week (it took about 20L) and this morning I gave it the last 15L or so that I have on site, and it's still nowhere near full.

With the oil topped up and its belly full of diesel, I got stuck into the digging. First up was the short run from the  pump room, up to the house inlet. This is rather a steep incline (about 1 in 2) and so I cut the first section from below, then manoeuvred up alongside the house to dig the rest.

I managed not to hit the Hebel, this time! :)

Digging backwards uphill was very tough going and so after about 5 metres in an hour I gave up, ate lunch and decided to attack from up at the tank site, coming down the hill backwards. First I plotted my course through the trees a couple of times, aiming to avoid sharp turns and the worst of the tree roots. With my line marked out in pink spray paint, it was into the digging.

Much easier! The first flat section was very easy digging indeed, achieving the first 5 metres in only 10 or 15 minutes. I'm using a 300mm wide bucket and only digging to about 300mm below ground level, so there's not a huge amount of soil to shift. Thankfully I'm mostly working in the topsoil - I'm finding that when I hit the red/orange subsoil I'm deep enough.

(I got so carried away with the digging and my rate of progress that I completely neglected to take any more photos! More tomorrow, I promise!)

By and large the digging was pretty easy going, with little large rock to be found. I did hit one reef that I couldn't move about 25m into the dig, but there's enough depth there so I'm not too concerned about it. There was one quite hairy moment where I crossed over a culvert beside the road, and the machine leaned over at a very alarming angle with me surfing it from the backhoe platform. I tried to right it with the backhoe arm itself and managed to get it wrong, and honestly I'm surprised it didn't go over sideways. I was on my feet and ready to leap in the opposite direction, but it just sat there at about 45ยบ sideways and chugged at me as if nothing had happened.

That was about the last of the excitement for the day, until at around 4:30pm the controls started convulsing slightly which is a clear sign that it's low on hydraulic oil, and the pump is picking up air. I gently nursed it back down the hill and put it to bed, and I'll have to make a trip to Seymour tomorrow morning for more oil if I'm going to get any further.

As it is, I made it about half way down the hill, which means there's only about 50m left to go. I'm amazed I got this far in one afternoon, as I was expecting this job to take a few weeks to complete. At last, something happens faster than expected!!

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