Wednesday 25 January 2012

Drill Bits and Dynamite...Part Sixteen ....Cut 7 and 8

Cuts 7 and 8 on the Sea to Sky improvement project were challenging in their own unique ways.
 The one tricky bit of cut 7, was the steep side-hill below the cut, that lead directly to the highway below. All the rock that needed to get blasted away from the lower side of the cut...automatically wanted to roll all the way down to the road below. The other part, that was both a blessing and a curse, was that the cut 7 rock was the softest rock on the site. This means a couple of things..one was that the soft rock would jam up the drill bits if you tried to drill too fast. On the other hand...if you had the drill rig all dialed in and paid attention...you could make record time on drilling each blast hole.


 The rock on Cut 7 was so soft, that after each blast the 385 excavator would just keep on digging and tearing it's way past the limits of the blast pattern. Instead of drilling and blasting every second day...we would have to wait for the 385 to hit harder rock that was drillable...this could take 3,4 or 5 days.
On the plus side, the soft rock didn't want to fly very far when it was blasted...so the guys could load it up a bit more and get fantastic breakage...but very little dangerous flyrock.


All the blasting at Cut 7 and 8 required the closure of the Squamish highway below us...to maintain the safety of the traveling public. Getting flyrock down to the road was almost impossible, given the conditions ( not completely out of the question though ) Rolling boulders, thundering down through the trees on the other hand, were very likely to happen. 

Getting a blast done and closing the road looked like this.
An estimated time of the shot was scheduled with the traffic control people and earthworks crew. ( we had to reserve a 966 loader and operator for possible clean-up on the highway )

The managers would let the M.O.T. ( highways ) people know that we were blasting and needed to close the road.

The blast was loaded and the wiring pattern checked by me and one other blaster to make sure it was all connected and timed properly.

As the time to shoot got closer, I would drive down to the highway below to monitor the road closure process...and be the eyes and ears for rolling rocks and debris coming down towards the road.

The traffic boss ( usually Felicia Lewis ) would manage the closure of all access to the highway. She had to work around strict guidelines on how long traffic could be held at any one point.

When the ready signal was given, the road was sealed off, and Felicia would zoom down the closed highway to confirm that there were no stragglers inside the closure. ( tourists would often pull over to take photos...not knowing that they were in a closure )

When Felicia gave the "all clear "...the blaster would sound the 12 warning whistles, and then shortly after push the firing button. ( we had an exemption to the standard blasting regs...we could fire the shot after a 20 second wait...instead of the usual 2 minutes )
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My job was to stay the heck out of the danger zone below, but be close enough to see if any debris hit the roadway. With the strict limits on closure times, it was important to locate problem areas as quick as possible.

When the rumbling stopped and we declared the blast zone to be safe, Felicia would drive through the entire length of the closure looking for any spots where rocks could have reached the roadway.

When we were all happy that there was no risk to opening the road back up, Felicia would radio her crew to open up all the closures.

There were several times when we had to have short road closures, when the guys were digging in the blasted rock and ran the risk of losing rocks down to the highway below. Several times we had to go into the treeline and deal with boulders that got hung up against the trees on the steep slope below the work area.
Cut 7 blast getting dug out and loaded to an articulating 6 wheel drive truck

Long view of Cut 7 getting mucked out...the tip of Bowen Island in the background...and farther out is Vancouver Island

Fog in the early days of working on Cut 7

Digging out a Cut 7 blast...looking towards large fill area

If you squint and use your imagination...there is a blasting crew getting a shot ready...you can see where things want to roll down hill to the highway once they get going

Cat 385 excavator working on Cut 7....Bowen Island in the background


Smiley Wayne in the 385 Hoe



Photo image of the very early stage of a Cut 7 blast
The main part of Cut 7 is on the right of the photo....a smaller section is on the left . ...the road above is the original access road that existed before the project started
Working on the large fill between Cut 7 and 8

In this pic...a lot of the Cut 7 work is done...you can see where the debris path was...where everything wanted to take off...rolling down to the highway

The fill between Cut 7 and Cut 8



The view from part of Cut 8 back to 7

Loading 6x6 rock trucks out of Cut 8

Cut 8...looking across to Cut 9. This is the site of the largest blast in Segment 1...approx 16 to 17,000 cubic meters in one shot....it was delayed to pull away from the sidehill when it was fired...that magic combination of good blasters mixed with luck and skill...kept the whole shot up on the bench where it belonged. If it would have went over the bank...it would have buried the highway and likely the rail line also.

Way early days...this is going to be the fill area between Cut 7 and Cut 8

Cut 8...the hoe down in the lower section is digging out a trouble spot where we couldn't find the bottom...no rock to pin the retaining wall to....it ended up being a long ways down!




385 Cat hoe loading out of Cut 8....this area was a bit of a choke point in the haul/access road....it was so narrow and steep that there no room to get by...if a major operation was in play


Helicopter view from Cut 9 to Cut 8


Line up of gear between Cut 7 and 8

Hoe working down in the "problem" area of Cut 8


6x6 rock truck leaving Cut 8 and heading to the fill area

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