We have this big ol' pile of horse manure out back, which we can't
spread out in the pasture because it is full of rocks that are just
about exactly the right size for causing problems with horses feet
(according to SWMBO, at least). The sizes range from sand to 3-4 inches.

Since clean, rock-free horse manure is pretty easy to get around here,
I'm assuming I cannot give it away. So I'd like to build a sifter for
the stuff, to separate the good rocks from the good fertilizer.

I'm considering making a big drum with a 1/4" screen, rotating it with
either an electric motor or a Vibration & Stratton engine. I'll load in
dirty manure in one end with my loader, get clean manure out the bottom,
and occasionally dump slightly odiferous rocks out of the drum.

What I need to know is:

1. Is this a good approach?
1a. How do quarries sift their rock?
1b. Is there something out there that I can get my hands on that does
this task? It doesn't have to look like what I think will work, it just
needs to separate the rock from the crap.
2. Anyone have any suggestions for screen? I'm considering expanded
metal, but it looks like I can't get really thick expanded metal with
1/4" holes. I'm afraid that the 18 gauge that it seems I can get will
wear too quickly, particularly if I get a big rock bonking around in there.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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