Basalt Crushing Technique 3

Basalt crushing tech 3
Basalt crushing tech 3

This is the third (and final) attempt to manually crush basalt gravel into usable particle sizes for the SPORE Pressure Experiment 1. The next technique will use a power tool.

This technique actually works pretty good. But it is EXTREMELY slow. This just doesn’t work for what I need and it really wouldn’t work for Homesteaders. I mean, they have things to do!

Cast iron skillet/ 5-pound wood splitter wedge/ PVC pipe


  • To make enough basalt particles of the correct sizes to start running the SPORE Pressure Experiment 1.
    • 2000 microns (#10 sieve)
    • 63 microns (#230 sieve)


  • 0.5″-1″ basalt gravel
  • 10″ cast iron skillet
  • 3″ diameter x 24″ long PVC pipe
  • 5-pound wood splitter wedge
  • Lightweight paracord (sorry, I threw out the packaging so I don’t have the specs)
  • A small paint brush
  • Geology screen sieve set
  • Personal protective equipment (PPE) Gloves
  • Impact resistant goggles
  • Dust mask (not needed)
  • Ear plugs (not needed for this experiment but would definitely be necessary if I continued for much longer).
  • Plastic bags for each particle size.


  • Similar to the other two. Instead of using a the concrete block I found a nice flat section of ground with some shade.
  • Before heading out I wrapped the wedge with the paracord so I can drop it down the tube and recover it easily.
  • The setup is simple. Put the skillet on the ground and stand the PVC pipe up inside the skillet.
  • Add some gravel to the tube (it will fall to the skillet). 1 piece at a time works best (least amount of effort). Too many pieces at once requires quite a few hits to break everything up.
  • Put the paracord wrapped wedge into the top of the vertical PVC tube. Hang on to the end of the cords. Release the wedge and let gravity do the work.
  • Pull the wedge up until it almost clears the pipe. Release again.
  • Do this a number of times. How many really depends on how much gravel you have in the tube and how large they are. More/larger pieces will require more hits.
  • Pull out the wedge and set it down. Lift of the tube and set it down. Brush the basalt fragments into the sieve and sort.
  • Put the tube back into the skillet and start again.
  • The first time I tried this I put a handful of basalt gravel in the tube. I found it could take up to 20 hits before all the larger pieces broke up. That gets kind of tiring if you’re doing it over and over again.
  • The second time I tried this technique I put a single piece of gravel in the tube. It only took 2-5 hits to reduce it to pieces. I then removed the wedge and dropped in another piece. Repeat this for about 3-4 pieces. then remove the pipe and place the crushed basalt into a container for future sieving.


  • This technique worked a lot better than the previous two. It required less effort, generated less waste, didn’t contaminate the sample, and was faster. At least I think it was faster. They all were really slow.
  • There was no basalt loss from the skillet. Yay PVC pipe!
  • Recovery of the crushed basalt was easy with the skillet and paint brush.
  • All of the equipment held up well and didn’t show signs of significant wear.
  • Even with all this, the process was very slow. It would take me a LONG time to get through all the basalt gravel I have.


  • Even though this technique worked, it was way too slow. The hammer/skillet/enclosed room thing might be faster (but messier and more likely to cause minor injury).
  • This technique would not work very well on Luna due to the low gravity. The wedge wouldn’t build up much kinetic energy using this set up. The pipe would have to be much longer, providing a much longer drop. And the process would be even slower as the Homesteaders waited for the wedge to slowly make it’s way down the pipe.
  • I’m done with the manual basalt crushing techniques for now. I now know it can be done with a little effort and a lot of time. Good to know. Now I can move on to a motorized mechanical option that will be much more efficient (and more expensive).
  • I’ve emailed several manufactures of equipment that I’m interested in with details of what I’m looking for. Hopefully one will have what I need.


wedge and pipe
wedge and pipe
Set up tech 3
Set up tech 3
results of 30 minutes with tech 3
results of 30 minutes with tech 3
results of all three attempts
results of all three attempts
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