Descend Downunder
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| The diving barge at Jounama |
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China Countdown..
It only seems like yesterday we got news that we had won the contract in Hong Kong – well its more like a couple of months ago and you guessed it we’ve been busy preparing manuals, presentations, exams, certificates and time- tables for our first course that is commencing next week.
We are running two different training programs whilst in Hong Kong one for Hyperbaric Workers, meaning the workers that are working on the tunnel boring machine under pressure. The second for Lock Operators, the personnel who put the workers safely under pressure. Its been a big job but we are finally on track and catching up on everything else, hence the newsletter being a little late.
Solomon’s Countdown..
Well, our Solomon’s trip is approaching rather quickly with only 8 weeks till we depart to the warm, sunny, white sandy beaches & turquoise waters of Gizo. Our trip is now full with tickets being issued shortly. We are going to have a pre-trip get–together so the group can meet and work out some final details.
Solomons Pre-Trip Getogether..
When: Thursday 24th August
Where: The Star Hotel, Albury
Time: 6:00pm
RSVP: By 18th August on 60411405 or dive@descend.com.au
Product Recall..
Scubapro have issued a product recall on their X650 second stage regulator. If you have not already done so please bring your regulator into Descend so we can check it for you. We can check it on the spot for you and if found to be faulty it will be replaced ASAP. Please note: Recall only on X650 NO OTHER model effected. See inside for more information..
Descend Trains Tunnel workers in Hong Kong  | | The site in Hong Kong |  |
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Due to our success with previous training on the Sydney Airport Rail Link Tunnel and the China Harbour Transfield Joint Venture Descend was again invited to tender for the contract of preparing and presenting the training package for hyperbaric workers and lock operators for the Kowloon Southern Link tunnel.
Descend won the contract in May and will train the workers who will be boring twin tunnels through soft ground below Tsim Sha Tsui, Hong Kong.
Since wining the contract it was all go, we designed both courses, wrote two new manuals, prepared two new PowerPoint presentations, designed the exams and certificates all with in about six weeks.
Descend’s first training program commences 26th July – 21st August inclusive where we will be training workers to work in compressed air conditions.
Our job is to train the workers on how to enter and leave the pressure environment safely and to train the man lock operators. (Recompression Chamber Operator) on safe lock operation. This includes a lot of normal diver theory including, basic physiology and physics and diving maladies such as decompression illness and squeeze. Of course decompression tables, regulations and fire safety are a compulsory part of the lock operators course.
Facts on Kowloon Southern Link
John Holland Tunnelling and Underground Mining and JV partners of Leighton Asia (Northern), Balfour Beatty and Kumagai Gumi were awarded the contract KDB-200 on the Kowloon Southern (railway) Link in Hong Kong. Contract value $350 million AUD.
The 3.8km Kowloon Southern Link (KSL) in Hong Kong will link the East and West Rail lines and run under the heart of the Tsim Sha Tsui district from East Tsim Sha Tsui station to Nam Cheong Station, the current station head on West Rail.
Contract KDB-200 is the southern section of the project, which runs from East Tsim Sha Tsui station under Salisbury Road and Canton Road to Jordan Road.
The scope of work includes the construction of the West Kowloon Station, Canton and Salisbury Road Tunnels, MTRC crossing and Salisbury Road cut and cover. Work will involve the excavation of twin 1.1km tunnels to be excavated by a Herrenknecht Mixshield TBM.
The Tunnel Works:  | | The Tunnel Boring Machine | |
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Two x 1100m tunnels, Canton Road to Salisbury Road built using a slurry shield Tunnel Boring Machine (TBM)
The Tunnels are 7.0m internal diameter and lined with 350mm thick segmental precast tunnel lining
Cross passage for emergency evacuation to meet safety requirements
Sumps for M&E requirements
Stage 1 track slab and walkway concrete.
Deep, Dark, Cold and Difficult.
By Des Walters  | | Checking divers mixed gas levels | |
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We always knew it was going to be difficult however this was not put into full perspective until the Snowy Hydro site representative came up to me, about a week before we left the site, and said "Well you guys are in the record books now". I wondered what stupid thing we might have done that deserved a mention but when I queried him he said "This job has never been attempted before in the Southern Hemisphere as it’s considered too difficult. Now your boys have done it".
When we started on site in March I had asked the Principal Contractor, Geotechnial Engineering, how long they expected us to take. About three weeks should do it was the reply. Principal contractors are always optimistic. Now 16 weeks later, after 84 working days on site, 364 mixed gas dives to around 30 meters and having expended over 4500 man hours on the job we were finally going home.
So what was so difficult? The job was in Jounama Reservoir at Talbingo. It is in preparation for a mini hydro scheme which will utilise the water released from Jounama into Blowering Reservoir and will be capable of producing enough electricity to power over 6300 homes. Snowy Hydro have decided to reuse the original low lever diversion tunnel to channel water into the new turbine. This tunnel was originally used to divert the river while the dam wall was being built. When the dam wall was finished in 1968 the tunnel was sealed, supposedly forever.
How they went about sealing the tunnel is interesting. Firstly they fitted two concrete stop logs into the pre-prepared stop log guides. These logs were 1200mm high and about four metres wide and 600mm thick. On top of these logs they fitted two 6mm thick steel gates, 6 metres by 4 metres, reinforced with 500 by 200mm RSJ beams positioned horizontally at 400mm intervals. They capped the gates with 6mm steel plate then poured 600 mm of structural concrete over the lot. They even managed to pour concrete into the guide slots around the left hand gate and then, just to be sure, they bulldozed 100 cubic yards of dirt and rock over the whole structure. Cover that with 30 metres of water at an altitude of 380 metres and a temperature of 7 degrees Celsius and that’s what we were facing. Oh, and did I mention that the water level can fluctuate up to 9 metres a day depending on the inflow to Jounama by Tumut Three power station. That makes deep diving very difficult.
We started the job, with eight divers on site, by establishing the barge and all of the heavy gear,then dredging to expose the concrete block. The next step was to break up the concrete to expose the top of the gate. We started with a hydraulic jack hammer however this was the hardest structural concrete we have ever encountered and the big jack hammer bounced off the concrete and hardly made a dent. We tried drilling a Swiss cheese of holes in the block to weaken it but with no result. We went up to a bigger pneumatic hammer and still no result. Finally we got in the big guns. A hydraulic rammer off the front of an excavator, mounted on a big RSJ steel beam and hung off the main winch did the trick. The only disadvantage was we had to put the excavator on the barge and extend the hydraulic hoses from the excavator to the rammer to be able to run it. The in water hammer and beam weighed about one tonne.
With the concrete dispensed with on the right gate we confidently attached the 30 tonne winch and tried a lift only to find we bent the main pulley supports. There was no way this was coming out in one piece. The solution, cut the gate into pieces. We attacked the gate with the Boroco ultrathermic cutter and cut off the top one and a half metres horizontally. With another big lift out it came. This process was repeated three times and the right gate was removed in four separate sections. Now it was time for the bottom concrete log but first we needed to uncover it. More long days of dredging. One hundred cubic yards is a lot of dirt and of course mixed in with it was a lot big rocks that needed to be moved by hand. The dredging eventually exposed the original lifting points and we confidently attached the 30 tonne winch and tried a lift only to find that we bent the 30mm steel rods that were imbedded in the block. Go to plan B. The concrete block is sheeted in steel so we cut hatches in the steel to expose the concrete then chiselled out the concrete to expose the 30mm steel bar and create new lifting points. This time the block lifts out.
On to the left hand gate. The rammer makes good progress in breaking up the concrete capping but it exposes the stop log guides that are filled with concrete. There is no way this gate will lift out of the guides. We decide to cut this gate twice vertically and remove about a metre and a half out of the middle of the gate and then by low slinging the lifting chains collapse the gate in on itself. The only problem here is that requires us to cut not only the 6mm steel plate but all twenty eight of the 500 by 200 steel beams. A very big job. With the centre removed from the gate we confidently attach the 30 tonne winch and it works but only on one side. Half the gate has not moved. We put the big hydraulic rammer back in the water and hammer the remaining gate to loosen it then it also comes free. There is still a problem. All of the structural concrete is left in the guides. Its about 600 by 200mm the full 7 metres height in both guides. Two more days with the rammer get the guides clean then another four days with the dredge expose the lifting points on bottom concrete log.
We confidently attach the 30 tonne winch, but, you guessed it, the lifting points bend. Same routine. We know how to do this. Cut the steel plate, chisel out the concrete and create new lifting points. We confidently attach the 30 tonne winch but this time the concrete log explodes and the winch pulls the lifting bar and the steel plate covering it out of the log. Now the whole thing has to be broken up and removed by hand. Well that’s pretty much how the whole job went so why should this bit be easy?
Well we are expected back in about six weeks time to actually fit the new gates when they are finally finished. We are really looking forward to that.
For photos of our job at Jounama select the link below:
http://www.descend.com.au/training/gallery/PhotoGallery.asp?AreaID=17&LibraryID=479&whichcategory=Jounama%20-%20Snowy%20Mountains
Handy Equipment Checks for every diver…
I recently received a dealers newsletter from Mares listing handy equipment checks that every diver can perform on their gear especially in between annual services and before that special trip away
Below is a list of the most important "details" you need to check on your equipment.
Have you checked the hoses on your regulator (second stage, octopus, pressure gauge/console, BC, dry suit) for any abrasions, deformations, nicks, or cracks?
Are there any cuts and/or holes on the mouthpiece of your second stage?
Can you see any small holes and or cuts in the strap on your mask?
Are there any cuts or cracks in the straps and belts on your fins, instruments, or computer?
After inflating your BC, do you notice any leaks in the seal of the buoyancy bag?
Have you checked that the instrumentation on your console is clean and operational?
Are the zippers on your suit perfectly clean and lubricated?
Are there any cuts and/or small holes in the neoprene of your suit?
Have you checked that the batteries in your flashlights and/or tools are fully charged?
Have you prepared your "dive rescue" kit?
After completing the checks listed above, if you found any of the issues mentioned, here is what you should do:
1) Visit your local dive shop to purchase or replace the hoses that show signs of damage. To prevent deformations in the hoses, especially near the metal coupling that screws into the first stage, we suggest that you install the corresponding hose cover. In addition, to experience greater freedom of movement try installing the special 45 or 90 degrees joint between the hose and the second stage.
2) Do you really need to put up with the discomfort of a damaged mouthpiece during your dive? There are various options of mouthpiece in various models and sizes to choose from. You can install the standard mouthpiece or a smaller one, depending on your needs.
3) Pull on your mask strap gently and look against the light to check for damage. If you find any, the replacement operation is very simple. In this case as well, there are various options to choose from, just make sure you get a split strap and silicon is the most comfortable. If your not big on spitting in your mask don’t forget anti-fogging solution!! Also great for that new mask that has a tendency to fog up.
4) To prevent troublesome (and in some cases, costly) surprises under water, if the fin or computer straps are damaged, replace them immediately! About the fin strap, if you have noticed any cracking, we advise you to replace both of them. If you haven't yet done so... why don't you try out the new Mares ABS buckles? You can use the new buckles on any Mares fin (and they do fit some other fin brands as well).
5) After you have fully inflated your BC, if you notice a loss of inflation after about an hour, the cause may be due to the presence of impurities, such as sand and/or salt crystals, in the over-expansion relief valve. This problem is easy to fix, by unscrewing the valve and cleaning it of any residue. If you notice air leaks between the hose and the coupling for the corrugate while inflating, the problem is almost certainly due to the O-ring located inside the hose. Descend can easily replace the defective O-ring in the hose.
6) Maybe you've never realized it, but when consoles scrape across the seabed (in addition to ruining the environment!!!), lots of impurities are collected inside the case, especially salt and sand. These impurities, besides ruining the aesthetics of the instrument cases in the console, they also partially contribute to the wearing out the pressure gauge O-Ring. We suggest that you carefully remove the tools from inside the case and clean them. In addition, using a retractable cable to keep your hoses well secure to your BC (or any other accessory).
7) I think that the feeling you get when, just before the dive, your suit zipper sticks, or worse, gets damaged: there's nothing worse. You feel alone and powerless! Then, when you realize that preventing this problem is as simple as using a tooth brush to clean the zipper, you can't help but get angry with yourself!! We also suggest that you periodically lubricate the zipper on your suit with special grease.
8) If you have noticed little holes and/or nicks in your suit, you can solve the problem easily by using a few drops of the special neoprene glue like Aquaseal. Small holes are easily fixed but if left till they become big holes it may call for a new suit altogether.
9) You can't show up for your most important dive with dead batteries!!! So, if your flashlight uses rechargeable batteries, check the charge and battery life of your batteries before you leave. If your flashlight uses alkaline batteries, replace them before beginning the season.
Also remember to bring at least one extra light bulb with you.
As far as computers are concerned, don’t forget to check the remaining battery power and if in doubt replace them with new batteries.
10) If your dives will take place on a beautiful but out-of-the-way island in who knows what sea, you can put together your own "dive rescue" kit including:
-1 regulator mouthpiece kit
-1 tube of silicone grease
-1 tube of neoprene suit glue
-1 mask strap
-2 fin straps
-1 pair of fin buckles
-1 hose retainer
-2 flashlight bulbs
-2 alkaline batteries for the computer
- assorted O-rings
Good – now everything is perfect! You and your equipment are ready!
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