BY DAVID KAREJWA
Dredging is very hard and tedious work at its best. The more we dredge, the more we realize how much time is actually spent moving oversized material out of the way.
Some pay-streaks don’t have any large boulders at all. Then again, some pay-streaks have an abundance of boulders—many of which are too large to move by hand. When this is the case, gold production results no longer depend on how well you can operate a suction nozzle; they depend on how efficiently the boulders can be moved out of the way.
Many of us started by using two-ton come-alongs to pull the boulders out of the way. And while this may work fine on a very small-scale operation, or an operation which only runs across an occasional boulder, it does not work well at all on a commercial scale.
Pay-streaks can be time and energy-consuming to find in the first place. Being ineffective at moving the boulders out of the way can greatly lessen a dredger’s ability to succeed. I have been dredging on a somewhat serious level on the Klamath River during the past four or five years along with a number of other serious dredgers. Together, we have innovated new boulder-pulling equipment concepts which have improved our sampling and production capabilities to an enormous degree.
The most comprehensive demonstration of underwater dredging I have ever seen is contained in Dave McCracken’s video, ” Advanced Dredging and Sampling Techniques.” Detailed winching and rigging techniques are also fully laid out with diagrams in Dave’s book, “Advanced Dredging, Volume 2.” These are highly recommended for those of you who will get serious about winching.
We found that a winch can be mounted on a floating platform, and the platform can be anchored out in the river behind our dredge hole. We use an electric winch in most cases, but new designs are including hydraulic winches.
The platform is anchored to the rear—either by cabling it to a boulder or a tree on the bank, a boulder or a group of boulders in the river, or to a dead-man placed in the river with tailings from the dredge dumped on top to anchor it.
The winch cable and boulder-harness extends down into the dredge hole. Also, the winch controls, on a cable, are waterproofed, and extend down into the dredge hole. When a boulder needs to be winched out of the hole, it is just a matter of slinging it, and winching it back, with all of the winch controls directly at your fingertips. This greatly improves the situation over having to put an additional person up on the bank to operate the controls of a mechanical winch, having to give signals, etc. It allows for single-person operations. While I don’t advocate people dredging alone, a lot of people do. If you are one of them, with this system, you are able to dredge for awhile; and when a boulder needs to be winched, you can simply sling it and drag it out of the way—just like that.
The old way required single-dredgers to sling the boulder, then go up onto the bank to operate the winch. When the boulder got jammed against some obstruction along the river-bottom, the person would have to go back into the water, try to free it up, back to the winch, back and forth, etc., until the boulder was finally moved out of the water. It was a nightmare!
One excellent advantage to a floating winch, we have found, is that the pull is also in an upward direction on the boulder. This helps slide the boulder more easily because of less friction along the river bottom. It also helps get the boulders pulled up and over other obstacles. Consequently, there are fewer problems with the boulder being jammed up while it is being pulled.
Floating winch platforms are relatively inexpensive and easy to construct. They don’t generally need to have much more flotation and size than an average 6-inch dredge. They are not very heavy, and they are easy to float around in the river. In fact, we use the extra deck space on ours to store our extra dredging and cleanup equipment, extra gas, etc.; the things we don’t like cluttering up the decks of our dredge. We place a portable motorized electric generator on the winch platform to keep the winch battery fully charged while we are diving.
Some commercial dredgers on the Klamath River have taken this concept one step further by placing the electric or hydraulic winch on the front of their dredge platform. The dredge is directly behind the hole, anyway. This normally requires an extension of the dredge flotation platform in the front to allow for the additional necessary buoyancy. The advantage to this concept is not having to move around two separate platforms. The disadvantage is not being able to pull the boulders far enough to the rear when you are dealing with lots of boulders.
When you are winching from the front of a commercial dredge, it is also important to keep looking up to make sure you don’t pull the front of your dredge entirely underwater!
This can also potentially happen with a floating winch platform, but it is not normally a problem, because the pulling point is generally from the center of the flotation, as opposed to directly off the front of a dredge.
One local innovative dredger recently came up with the idea of mounting a winch on the front of his dredge in a backwards direction. By also mounting a snatch block under the center of his dredge, under the sluice box, then the pulling point of the winch is centered better on the dredge’s flotation platform. This helps eliminate the problem of submerging the forward part of the dredge.
One point to remember is to never tie off the rear of your dredge to a high point on the bank, or to a highline across the river, when you are planning to winch off the front of the dredge. This type of rigging will pull the back end of the dredge up into the air during rock pulling!
The biggest problem we have run into with floating winch platforms is in the electric controls. We have yet to find an underwater control box on the market which is designed for electric winches. So we have had to waterproof the standard control boxes. This is not all that difficult to do, but it is only temporary. Every few weeks, we find ourselves taking the box apart, and having to rework it.
There is also a potential safety hazard with the electric winches, in that if the controls short-out underwater, the winch can simply start winching! We have learned to create a quick disconnect on the electric cord near the control box. If we lose control of the box, we can unplug it, and the winch will shut down.
One important safety note on this: If you create a safety quick connect using extension cord plugs of some kind, make sure you put the female-side on the power cord. This way, the power cannot be shorted across once the cord has been unplugged. This lesson was learned locally the hard way when a dredger unplugged the control box and dropped the cord into his aluminum boat. He had the cord rigged with a male fitting. The male posts touched the aluminum of the boat, and he was winching!
While it is not particularly difficult to do, it is a bit involved to waterproof the control box to an electric winch—too involved to go into in this article. We use a fifty-foot #14 extension cord; we use a product called Dip-it, and we do a few other things to avoid making the modification so permanent that we cannot easily get back into it to re-do it when necessary.
The advantage to hydraulic winches is in having no problems with the control box. No electricity! This is why I believe the best future platforms will be utilizing hydraulics. For dredge platforms, it is not too difficult to mount a hydraulic pump directly to the dredge motor.
I hope this information has been of as much help to you as it has been to us dredgers up on the Klamath River.