Our club is also reclaiming our lead from the 50 year old backstop. In
our case the backstop is just dirt, and plenty of clay as it turns out.
We dug up about 100 cubic yards of dirt and piled it in large windrows
to dry out all summer, tented under tarps. I have put together a nice
line of equipment to sort the bullets out.
We start by dumping the dirt into a Royer 120 dirt shredder which
pulverizes the dirt and throws it onto a vibrating screen machine that I
designed and built. The sifted dirt falls onto a 30' long grain
elevator, which piles it back on the range. The concentrated
lead/gravel/clay clumps roll off the sreeen onto a small wagon, which we
haul into a pile.
So our concentrate is similar to what you start out with. We have one
member who has a lot of gold mining equipment. We have done a test run
using a gold sluice and it looks very promising. When the weather gets
better we will use his larger sluice to trap the lead, leaving a pile of
tailings to place back on the range.
The big problem we have is large clumps of clay which will not feed
through the shredder. I just bought a old hammermill from a landscaping
business. I am looking around for a suitable engine. A Yanmar 22 hp
diesel just sold on eBay which would have been perfect, but it was 300
miles away. There is a huge equipment auction coming up in a few weeks
that has dozens of engines, I'mm coming away with one of them!
I am building two smaller conveyors from parts I got at HGR to feed into
the hammermill and connect the mill to the shredder.
You should keep in mind the environmental issues. The EPA does NOT
regulate operating ranges, but they do regulate the ground and surface
waters, so any wash water needs to go back into the backstop if it has
lead in it.
The EPA does have a very practical manual titled, "Best Management
Practices for Lead at Outdoor Shooting Ranges", which are recommended
guidelines. If you don't have it, you can download it at:
http://www.epa.gov/region2/waste/leadshot/download.htm
As we process our dirt, I adjust the Ph with lime, and add phosphate to
bind any lead that does get dissolved, as per the EPA manual. I add a
measured amount of the chemicals to each load of dirt that goes in the
shredder.
--
DT