Not sure Deas... They were in very hard limestone on this job....Seems the dozer crews had all they wanted to strip the topsoil off to keep ahead of it. 

Hi, TimT.
Now why did I think that material looked like limestone in the video?

I have worked limestone in the past. Some of it is not all that hard but some of it can be a bit of a challenge - to put it mildly. A fair bit of the cities of Perth and Fremantle in Western Australia is built on limestone - makes pretty good road base course when handled properly.

Thanks again for the video and the info.

Just my 0.02.

HI Deas,
My dad had a quarry north on Perth in Nowergup, we cut the limestone with carbide tip saws, we used a ex Telecom D8K to strip to get a reasonable floor to cut the stone, we had a fella that worked in Shay Gap for years on the Dozer, he would pop the cap stone apart all day on about 200lt of fuel, never got revs over half all day just picked thru the stone to find a gap to get the pick in and lifted rocks all day, yes you could fell the earth move when they let go, many times I did see the front idlers off the ground to be lowered gently back down with a touch of power and out the rock would come, Old Ian was a great operator and loved the old machine, wasn't to keen on the D8N we bought later. The neighbouring Quarry had a D9G then later a 475 Komatsu to get thru the rock for the saws to get to.

Hi, Busso.
It's great to hear from somebody over thataway. I was born in Mount Hawthorn and lived in various parts of W.A. until I was 28, when I tranferred to Sydney with Leighton Contractors - took 28 years to get back there - been watching a bit of Les Hiddens up around Kalumburu the last 1/2 hour or so - I spent 7 months on Mitchell Plateau in 1971 - GREAT country.

I worked at the original Mount Goldsworthy mine in early '68, before I went to work on the Mount Newman iron ore rail project for 11 months.

I think I could get to like 'Old Ian' - sounds like my kind of operator. The D8N was substantially less machine than the D8K.

Thanks for refreshing the memories.

Just my 0.02.

HI Deas, for some reason I think you mentioned somewhere on the BB you were from the west, My mom was born in Mount Hawthorn as well, Ian did 13 years in Shay gap (he was one of the last to leave after rehab work), he spent a few years at Goldworthy before it shut then moved to Newman, he was on telecom D9G ripping the trench to lay the phone cable in when it originally went from Port Hedland to Newman for 2 years, they had 3 dozers ( one to rip, one to push ripper, one to lay cable), he did say he was asked to tram back 120km to re-rip a rock patch about 300m long( no so happy about it when he spoke of it), then started at BHP Mount Whale Back, his 2 sons and a Daughter worked there as well, they all worked together before the FIFO started as residential town back then, The top end has some awesome country to see, I was lucky to spend time at Koolan and Cockatoo island with iron ore from 2012 for a couple of years, each flight in and out was the best scenery over horizontal falls.

Hi, Busso20.
GREAT memories of times that likely will never come back. I got to work on some jobs that people find hard to believe too. F'rinstance, I cut the first ever track into Mitchell Falls one Sunday morning in 1971 and a helicopter from Bristow's met us there and flew us over the falls - for free. You get to pay bulk bucks for that today.

Just my 0.02.

Hi Deas, yes your right, I worked on the clearing for Busselton bypass, a fella from Telstra came down from Perth in a chopper to survey the optic fibre that was already in to avoid pulling it out with traxcavators, the supervisor asked if the pilot had enough time to fly around the town? yep he did 4 workers went for a spin along the job, yes a bonus to being there.

things that insurance has killed off. my 3 great uncles all met up in a chopper once to look a qld main roads job. uncle dezi worked for main roads, uncle jeff was sales manager for pro-main plumbing supplies and uncle ron was the geotech drilling contractor, no one twigged till they all said hello brother, hello brother.

years ago when dad was part of rotaract they got to have a tour through fred haigh dam on mondouran qld and the control room for the bundaberg district irrigation water supply as one of the rotarians was a high up in the IWS so he organised a tour they went down inside the tunnels in the dam wall.

Hello Deas, Thanks for posting this. I hate to show ignorance but I have tried to figure what is being accomplished in the trenching video. I keep thinking of the ol' Army basic training "dig a trench then fill it back up." The back-filling crew is right behind the rock saw, the same material (although crushed) is used and nothing else is added to the trench. The only reason for the trenching I can think of is to provide a way for water to penetrate the rock layer. The project is too large to be a "dog & pony show."
Thanks,
Craig

Hi, seiscat.
They can do a number of things with it, depending on attachments and following crews, from installing water barriers by adding cement, lime or other materials to the excavated material to laying deep cables or drainage. Even by simply excavating the material and putting it straight back in, they would be creating a drain line 'coz there isn't much fear that the material going back into the bottom of the trench would be very well compacted at 100 feet down and it would certainly be more broken than the original material around it.

If you read through TimT's post above, he says that they were digging a trench for a water supply line in that video and the first one in my in link was doing a water barrier project in Florida. I'd guess that they are just not showing you the laying of the water supply line prior to the backfilling. After all, who doesn't lay water lines like that most days of the week?

Just my 0.02.