Moving Large Rocks

[goldtimer]

Hello all
What do you think is the best way to move large rocks out of the way?
I have found an area in a river, with a lot of large rocks that are very difficult to move.

Do any of you know of any good winches that might do the job.
Or any other methods you would recommend?

Cheers

[roscoe]

Hi, Gt, how large is large? 1-2-3 metres across? Bigger? If they are locked together, you will have to pull a couple to give you working room to move others.
Power winches are heavy to move and set up. We finished up with a 5 ton Tirfor and snatch-blocks if we needed angled or increased pull. Car jacks (screw-type) work well if you get squatties. Hydraulic jacks bugger up if you try using underwater.
Usually you only need to lift them a few inches, clean out the first third to half, then roll them a tad to clean out the other side.
Now if you`re talking about boulders sitting on top of boulders------------ ;D

[goldtimer]

Hello Roscoe,
The larger rocks are about 3 meters by two meters and are pretty heavy.
I have a hydraulic Jack, but I haven't tried using it under-water.
I might have to look around the wreckers for a Screw up Jack instead.

G.T.

[roscoe]

Hi, Gt. When you jack up boulders, don`t rely on one lift point as rocks tend to screw off jacks. Same goes for propping up using stacked rocks. Take a few short lengths of 4X2 hardwood and prop with them.

[goldtimer]

Thanks for your advice Roscoe
I'll try that and se how it goes.
Thanks
GT.

[RKC]

G'day Goldtimer,

There used to be some quiet detailed information on moving river rocks in one of Dave McCrackens books. I think his books that are presently available have all been rewritten and updated ... nevertheless the information might still be in the new books. Moving rocks is mostly common sense but you might get some good tips from McCrackens book on the mechanical details.

What needs to be taken into consideration before getting into the river, is if the extra effort might pay off. No matter what mechanical means you utilize to move the rocks there will be a great deal of time taken up which will slow the whole dredging process down considerably. So ... the gold has to be there in quantity to make it payable (more so than you would normally consider acceptable).

I don't have much experience moving rocks and I've probably walked away from many potentially rich rivers just because they appeared boulder chocked. When I first saw NZs Lyell creek many years ago my immediate impression was that it was far too boulder chocked to be worth dredging. But another dredger who came along later was not so easily discouraged and he did extremely well out of the Lyell (however he would have earned every grain he got and there would have been no easy gold from the Lyell).

Many of the auriferous rivers of South Westland here in the South Island of New Zealand are incredibly boulder chocked ... so much so that I suspect that even if an excavator was used in the river, the boulders would still be extremely difficult to move.There are incredible amounts of fine flood gold spread throughout these rivers and all that makes these rivers an uneconomic dredging proposition is their boulder chocked nature. The only way I have ever considered that they might be economically dredged would be to just dredge between the larger boulders taking only the first foot or two off the top and not attempt to go down deep. Which might or might not work ... might be worth a try for someone however. What could prevent that however is that boulders are sticking out well above the water line. If there was ... say, a few feet of water flowing above the highest boulders then it might be possible. And to dredge in such shallow areas only a suction nozzle could be used as there would not be enough depth to prime a power jet.

There is a section of New Zealands famous Arrow river (well upstream from Macetown) that has some of the largest boulders I have ever seen in a river. And when I saw that section while flying over it in a chopper I was curious about it and I then read up on the geology of the area, which told me that the boulders came from a volcanic eruption (from the hill just south). And the mining records I also read mention that that section of river was never mined. The river above and below the section was mined and both sections produced extremely rich gold to the miners of the late 1800s. It rather made me wonder if there is virgin gold remaining under those boulders.

One river I once dredged in Nth Queensland was very boulder chocked but I gave it a try anyhow because the biggest boulders were at most only the size of less than a meter in diameter. But all the boulders were packed solid and not easily got at to be moved mechanically. I dredged around the boulders where I could and got good gold, but my mind set at the time was that I had to go down towards bedrock to get the best of the gold. If I had just done the top few inches between the boulders I probably would have done well (hindsight is wonderful). Anyway the gold is still there ... unless someone has got in there since who put more though into how to best dredge it.

Regards,
Rob (RKC)

[Deleted]

big digger with a root rake

[gmrigger]

gmrigger, I work with ropes and winches and moving things around in places that do not have machines. Jacks are good to move things on solid safe ground when moving large rocks you are very close to something that can hurt you or even kill you in a second. The main disadvantage with jacks is the small lift hight they have and they are designed to work in a vertical format . Once they are used on a angle the base plates on the jack can brake if not properly supported, this is more to do with larger jacks 15t +. Working with large rocks can be very dangerous and not having the right know how can lead to harm, underwater this is even more dangerous as the jack can slip on the stream bed material. I would not recommend someone with no or little experience to start playing around with larger rocks. Winches also have the potential to cause injury. It is not just a case of getting a big winch and start pulling a rock. One think that a lot of people do not take into account when winching is the holding strength of what the winch is attached to. When a big rock rolls or falls even a short distance a great load is put on to winch anchor, often the person operating the winch is not in a good position to get out of the way quickly, when this happens there is risk from the winch braking from the anchor or the wire rope braking. One of the most important things to consider when winching rocks is the correct angle to pull the rock from, as Rob has said, sometimes it is needed to remove other rocks first, rigging is about good planing in advance of work, once you have started moving the rocks and you have not work out your plan correctly, you will have a lot more work to do to get things moved again. Once a big rock has rolled onto somewhere that was not intended it can be most difficult to move it again. Very large loads can be applied to a small diameter wire rope and a good knowledge of wire rope fittings ( wire rope grips, shackles and wire rope safe working loads ) are needed to do this work safely. I have seen many times people with very little experience doing work that was very dangerous without them knowing the risks of what they where doing. Many old miners where very good at rigging work and they did not have the gear we have now, as with many trades these skills are not often seen these days. My recommendation would be to find someone with these skills to give assistance. Cheers Gavin.

[gmrigger]

gmrigger, I have mentioned in my last post matters that one should conceder befor starting work to keep safe. Three months ago a man in Christchurch lost his leg when a winch rope slipped. I will now list a number of different winch devices that can be considered for moving larger rocks and some of their advantages and disadvantages. These are my thoughts and others might have a different idea of things that me.

Each situation will have different factors.

Main considerations
1. What will be your means on transporting the winch to the site.
2. What size of rocks are you are moving.
3. How many rocks are you moving
4. How many people will be involved
5. How much do you want to spend

Tufor, come-along
These are useful in the fact that they contain a long Lent of rope 10 - 20m+ and there is the ability to free spool the wire rope through the winch so to save a lot of time winching in slack rope. Units of up to 3t are quite common and I have seen units of 5t as with any hand operated winchs things start getting heavy. The larger units seem to be expensive even when second. One disadvantage with these winches is that they use a special rope construction, it is very important to not kink , or pull this rope over sharp objects as once it is kinked it is very difficult to free spool the rope through the winch. These winches are slow and you will get fit quick using one all day.

4x4

If you can drive to your rocks with a winch mounted on your vehicle then you have it made very simple. Old tow trucks are cheap with good winches. I have used with a friend of mine an old Bedford tow truck to move rocks and to get the dredge out of the river when the river was near to the road, the rope was 50m long.

Electric recovery winch 12-24v dc.

These winches are found on a lot of 4x4 these winches have a good working load and use rope from normally 10 - 16 mm on larger units, these winches free spool are good value for money and if modified for working as a separate unit away from a vehicle I think are a good option . Buy a good quality unit Wran -Thomas are good units. Some engineering will be needed to get the unit set up to work independent. Batteries are needed and this adds expense and weight to the winch operation when used a lot a good idea would be to have a small petrol generator charging a second battery so when one battery goes flat there is a full charged replacement ready. A small petrol motor and a car alternator will not cost very much and they are easy to get . One big advantage is that you are able to run a remote controller from the winch, this allows you to be out of the line of pull from the winch in case something lets go and if this remote is made long enough you can see if the rock is moving giving you more control over the winching operation. Other winches have you a long way away from the rock and you are in line to get taken out from recoil from a rope braking or the rope sliding of the rock. This unit will be more expensive to set up but will give you a lot easer time of winching than using a hand winches.

Petrol Diesel driven gear- hydraulic winches.

I have not seen many of this type of winch that would be suited for this work, when using gears to provide drive for these types of winches most I have seen get large and all the gearing and bearings start to get expensive. In dry locations dust getting into the bearings is not going to be a good thing. The winch shown in advanced dredging is a good unit but expensive. Most of these winches require a brake band to hold the drum this can be another risk area from brake slippage. All of these types of winches are going to be heavy, so access to the site will be by vehicle or helecopter.

Leaver chain hoist

These are heavy when they get to 3t the chain length can be long I have a 3t unit with a 10m chain. these free spool and are not expensive to get second hand the bigger units are not as sought after as the smaller units. They are easy to move around and reset. I use these winches lots in my work and find them to be the best thing for a general hand operated winch. They can work in any position.

Chain blocks.

Can be used for non vertical winching, are heaver than leaver blocks. The multi fall chain blocks can be got cheep when rated 3t + as not many people want this sort of weight lift. Forget the older types of these blocks as you will need a crane to lift them.
You can derate the blocks from a multi fall to a double or single fall chain to increase your length I have a 5t block 8m 3 fall chain 16m@3.3T twin fall and 24m @1.6t. The endless chain used for lifting often gets caught in all sorts of things and well be frustrating after a while also a lot of dirt will get into the chain block. This chain can be changed to rop if used a lot for pulling.
The biggest disadvantage is that there is no free spool available on newer chain blocks wind in then wind out and things are going to be slow. The older worm drive chain blocks have free spool and are good in the fact that they are very simple in operation and are easy to keep clean. They are still heavy. All those rock would not be there if those old fellas had any of the gear we have now.

I will next give information on chain, slings, wire rope and fittings.

Cheers Gavin.

[roscoe]

Good stuff, Gav. keep it coming. Most of us learn from on-the-job training and we sometimes get it wrong. We draped sandbags or coiled a chain along the winch cable to avoid losing a head, but you might come up with something better.

Another of my mates said bugger lifting rocks, I`ll just blast. He rigged up a 1 1/2inch hose as a jetter and washed everything around boulders out to a central suction point. Worked for him as he hating diving or getting wet. ;D

[gmrigger]

gmriger, back again.

Wire rope

Two main types of rope are manufactured. Non wire rope core and independent wire rope core. In independent wire rope core ropes IWRC ropes. The former in the center of the rope that the outer strands of wire are laid on is a steel rope, this means that the center of the rope is steel and will resist crushing like when wrapped around a winch drum it has more steel in it so will also have a greater braking load for the same size rope. Disadvantage it will be less flexible in the smaller diameter ropes like most dredgers will be using this will not matter to much. If you use a non IWRC rope on a winch the rope will quickly flatten. This rope is not intended for winch drums.

Rope construction.

Ropes are listed as outside diameter, type of core and the lay of the strands, this is the direction the wires are rotated when the rope is made. The number of wires bundled together form a strand.
Example 16mm 6 x 24 IWRC this rope has a steel core it has 6 strands of 24 wires each wound around the central wire core.
Not many people understand that there is a great number of different wire rope constructions designed for different jobs.

General lifting
Non rotating lift ropes
Rope used on pile driving monkeys
Static cable ways
Endless sky tow chairlifts
Fishing ropes with left and right hand lays to spread the net
Tofor block rope

these are just a few, there are many many more all made for certain job.

Non rotating rope will not go well on a winch, its construction when pulled over a small diameter drum will cause uneven core slippage the inner wires will not slip as far was the outer wire and all of a sudden then the rope is backed of from being under load all of a sudden the rope can look like a birds nest with wires sticking out from all over the place.

Rope flexability.

The more wires in a strand the more flexability the rope will have.
A 6 x 24 rope will be more flexable than a 6 x 19. The smaller wires in each strand will be more prown to damage. A larger wire will not get broken as easly as a smaller one that is my reason to use wire ropr for winching only in a straight line pull. Chain or small wire rope slings can be used to attach to the rocks.

Wire rope fittings.

Wire rope grips.
These are used to place a eye in the end of a rope for attaching shackles and hooks or the eye can be constructed around an anchor point. For wire rope sizes under 24MM 3 wire ropes can be used. It is very important to know that way round a wire ropes gripe is to be placed on the rope. When you look at a WRG you will see a u bolt with threads and nuts at the ends this u bolt is placed over the tail side of the the rope, the piece of rope that dose not take the direct line of pull, the reason for this is when the WRG is tightened it will crush the outer strands of the rope . The tail side of the rope is dose not taking the load. If the rope is used again or the eye is to be removed or shortened the main part of the rope remains undamaged. 90% of the braking strength of the rope can be achieved by correct placement of wire rope grips.
It is also very important to have the correct wire rope size to match the rope diameter. The grips would be placed around 6 rope diameters apart. example for a 10mm rope the spacing will be 60mm. Use only certified grips not commercial grade grips. Commercial grade grips are flat on the of the grip that the u bolt goes through giving much less holding force on certified grips the base of the grip is grooved to suit the rope and this when tightened will hold the rope secure. Most grips are galvanized or zinc coated.

Thimbles.

These are preformed eyes that fit inside the rope eye they take the load of the shackle or hook and protect the small wires on the outside of the rope from excess load. They should be matched to suit the rope size.

Shackles.

These look like a u bolt except they have eyes on the ends one hole will be untreated the other threaded. The same as when you attach the safety chain to your tow bar. A threaded pin is inserted threw the hole and screwed into the hole opposite. On some special shackles there is a bold to go through both holes this pin is secured by a nut. Most shackles have a threaded pin. Shackles are used to secure fittings to the eye in the end of the rope. Certified shackles should be used. The working loads are usually a minimum of 16% - 20% of the load that will break the shackle.

Chain.

Chain slings can be very useful for moving rocks as a ring can be attached to both ends of the chain, or a hook can be placed at one end instead of a ring. The chain is places around the rock and one end of the chain is passed back thought the ring, the free end of the chain is attached to the winch rope by a shackle or hook. When the winch rope tightens the chain will pull up on the rock this configuration is called a choker the same as a dog chain.
The chain will be much easer to place around a rock than a wire rope. Wire rope do not like to be pulled over edges like on a rock also if the rock moves there is the chance that strands of the wire rope will be damaged. Ropes should be used for straight line work only or used through a block to change direction.

Blocks.

This is a u shaped pulley that a rope is to go through it is designed to change direction to the rope or by arranging a number of multi pulleys blocks top and bottom of the lift or pull a much larger lift or pull can be applied this will come at the disadvantage that much more rope will be used.

Snatch Block.

These blocks have a hinged side plate retained by a pin removing the pin allows the rope to be placed over the pulley without needing to thread the entire length of the rope through the block.

Cookes have a good range of fittings and will assist you with you questions
Cheers gmgigger.

[roscoe]

An alternative to moving a big boulder is to crack it. There are a number of two-part epoxy-based non-explosives like Bristar and Dexpan that are used in demolishing massive concrete foundations. Bristar is available in Australia. You either drill a series of holes or fill a crack with the mix and let the epoxy expand over a period from hours to overnight, depending on which formula you buy. No danger involved, just a few precautions, and you don`t have to bag over the holes/cracks. We used Bristar on a few cracks and it worked well.
Never got around to using it underwater, but I imagine if you seal it in plastic bags until you get it placed, it should work O.K.

www.bluecirclesoutherncement.com.au/Docs/Product/PackagedProducts/Product_Packaged_140706_162500.asp?AUD=BCSC_PackagedProducts&site=BCSC&toggleItem=1

www.dexpan.net/nonexplosivesblastingdemolition/product_dexpandemolitionagent.html

www.crackag.com/index_e.asp?gclid=CKSMvYue75cCFQ0upAodPyWXBw

[goldtimer]

Hi Guys,
Thanks for all of the very valuable information
I Didn't realise that there was so much involved in moving these large boulders.

Rob's probably right- there's a lot of time and effort involved, and you have to be getting good gold to warrant moving the larger rocks.
I have a spot lined up to do a bit of sampling, and I'll try moving some of the larger rocks and see what amount of gold I get.

If you don't hear from me again then the wire rope's got me....
Have a golden 09
GT

[RKC]

G'day,

A couple more links to add to the links provided by Rosco

micro-blaster.com/index.htm

www.demolitiontechnologies.com/