MJB
matt
After a recent prospecting trip I brought home a conglomerate type of rock that I picked up from an area where deep lead mining had taken place. I crushed the rock in my small dolly pot and was blown away to find a few nice little chunky bits of gold in it. I thought this was very interesting as these rocks are everywhere at the old diggings and I figured if it was consistent enough....and I could crush it...then it would pay handsomely.
I set about researching and looking at other rock crushers on the market but on my small budget it meant that I would have to build my own. So when I had a spare few minutes at work I started making it. I decided on the hammer type rotor with fixed blades of steel made out of 40 x 10 mm flat bar instead of the more popular chain type crusher.
The biggest problem I faced was what type of grate to have on the bottom to allow the crushed ore to filter out. The slotted style appealed to me but I thought fabrication of that with narrow enough slots might have been to tricky so I just drilled 2 mm holes in the drum. I countersunk the holes thinking it would act as a funnel to allow the material to better find its way out but after an initial trial I found this only allowed larger rock chips to get caught in the 'funnel' and block the holes. I ended up cutting the drilled section out and fabricating a slotted mesh, the slots measuring about 1.5 -2mm in width. This seems to work fine as it does not clog up and the dirt falls out easy. The only down side is perhaps the crushed dirt is not as fine as you may see on a commercial crusher.
The rocks in question??
the rocks pre crushed ready to go in the crusher
the crushed rock
some little chunky bits of gold
Now after crushing some of these rocks I have found that some have good bits of colour in them and others are completely barren. I have to sample and figure out which ones by appearance have the colour and which ones are worthless. I may end up just crushing the whole bucket load and running the dirt through my dry blower to concentrate it down a bit. Will keep you posted.
Cheers,
I set about researching and looking at other rock crushers on the market but on my small budget it meant that I would have to build my own. So when I had a spare few minutes at work I started making it. I decided on the hammer type rotor with fixed blades of steel made out of 40 x 10 mm flat bar instead of the more popular chain type crusher.
The biggest problem I faced was what type of grate to have on the bottom to allow the crushed ore to filter out. The slotted style appealed to me but I thought fabrication of that with narrow enough slots might have been to tricky so I just drilled 2 mm holes in the drum. I countersunk the holes thinking it would act as a funnel to allow the material to better find its way out but after an initial trial I found this only allowed larger rock chips to get caught in the 'funnel' and block the holes. I ended up cutting the drilled section out and fabricating a slotted mesh, the slots measuring about 1.5 -2mm in width. This seems to work fine as it does not clog up and the dirt falls out easy. The only down side is perhaps the crushed dirt is not as fine as you may see on a commercial crusher.
The rocks in question??
the rocks pre crushed ready to go in the crusher
the crushed rock
some little chunky bits of gold
Now after crushing some of these rocks I have found that some have good bits of colour in them and others are completely barren. I have to sample and figure out which ones by appearance have the colour and which ones are worthless. I may end up just crushing the whole bucket load and running the dirt through my dry blower to concentrate it down a bit. Will keep you posted.
Cheers,