Molecap Gingin - I took a petrol pressure washer & 1000 litres of water to excavate... is this bad?

[Dude468]

A couple of years ago I took a 3000 PSI pressure cleaner, with a custom made adjustable recirculating manifold so that I could adjust pressure down to almost 20 psi, as well as a trailer with 1000 litres of water to the Molecap hill in Gingin. I used this to excavate at high speed mm by mm, but at an amazingly high rate of speed. I found a whole bunch of stuff including a 6 inch bone that had clearly been ingested by another animal and showed signs of partial digestion. I found all sorts of teeth.

 

The process basically involved sweeps along the face of the chalk/greensand and when any item of interest showed itself, I switched the pressure cleaner down to a very low rate to carefully go around the items and remove them, as well as using other hand tools. I have never heard of anyone else using this technique before, it unbelievably efficient and not as destructive as it sounds, however I am just curious as to whether this is frowned apon by the palaeontological community? 

 

[jpc]

This was used a lot in the mountains of Colorado for gold mining in the late 1880s.  It made a right mess of the area, but I don't know the answer to your question.  

 

[Dude468]

8 minutes ago, jpc said:

This was used a lot in the mountains of Colorado for gold mining in the late 1880s.  It made a right mess of the area, but I don't know the answer to your question.  

 

Those water monitors were a lot more harsh than my technique, which uses fully adjustable pressure using the custom bypass manifold which dumps water from the pressure gun and recycles it back to the tank. This means I can use anywhere between 0-3000 psi to carefully strip back the walls of the quarry. 

[FranzBernhard]

No experience in digging with this sort of equipment, but pressure washers are quite useful for cleaning sturdy stuff. They are amazingly efficient, but usually not too harsh. And you are having the perfect setup with full control over pressure.

 

The only drawback I see:

3 hours ago, Dude468 said:

trailer with 1000 litres of water

You need to have some water nearby or vehicle access.

 

Franz Bernhard

[connorp]

I know of at least one commercial collector who used a power washer. The fossils he was hunting were usually preserved on bedding planes, but were covered by a thick layer of shale which he removed using a power washer. This can of course damage specimens, but when you're trying to excavate the entirety of a small quarry in a season, there is not much other choice.

[FranzBernhard]

3 minutes ago, connorp said:

The fossils he was hunting were usually preserved on bedding planes

Would you like to give a hint what these fossils were?

Franz Bernhard

[connorp]

39 minutes ago, FranzBernhard said:

Would you like to give a hint what these fossils were?

Franz Bernhard

Trilobites

[Ludwigia]

I recently saw a tv show about mammoths and other ice age mammals in Siberia and watched them using this method to extract among other things mummified mammal remains from the permafrost. Messy but efficient.

[FossilDAWG]

What are the local regulations regarding environmental impact?  Without before & after photos it is hard to envision the process in your specific circumstance without being familiar with the size of the outcrop, the amount of sediment you removed, and where all the water/sediment went.  Something that sounds similar was used by a collector several years ago along the bank of the Lumber River in South Carolina.  In that case he mounted a water pump on a boat and used it to blast cut banks along the river to recover shark teeth.  He did so much damage to the river bank, and dumped so much sediment into the river, that the county administration banned all fossil collecting along the river.  Many miles of river bank have been permanently lost to collecting .  I hope you are not doing that kind of damage.  Also I read that the quarry is on private property; if that is so I hope you had permission to apply this technique.

[FranzBernhard]

10 hours ago, connorp said:

Trilobites

Thanks! These are already on the tricky side with a pressure washer, but it really depends! Have you seen the results?
Franz Bernhard