MBMMLLC.com: Gold mining hammer mill maintenance and operation video

MBMMLLC.com: Gold mining hammer mill maintenance and operation video

This is Jason Gaber with Mt Baker Mining and
Metals, and I wanted to do a video of operation and maintenance of our hammer mills. This
is a 16” x 12” hammer mill, and it’s rated at between 1 and 2 tons per hour, depending
on the screen size you put in at the bottom. It’s powered with a 15 horsepower, 3-phase
motor. And it can be run both dual voltage at 60 hz and dual voltage at 50 hz, for some
of our international customers. Ball door also makes a 15 horsepower single phase motor
that we’ve put on these machines as well, for when 3-phase power is not available. We send the units with fully-enclosed, OSHA
approved belt guards, and we have a variety of hoppers we can put on here. This customer
is going to be feeding with a small conveyor. It should be noted the rotation of the hammers
and the shaft of the hammer mill, so as the material is fed down into the mill, it gets
thrown back against the case, and crushed against the case, rather than if it’s spinning
the wrong way, it’ll go right into the screen and will wear out the screen much faster. It’s important to have a fairly consistent
feed rate with this mill, either shoveling or metering in with a bucket, or meter with
a conveyor. The other thing with overfeeding, is if you
start to see material, water, and crush material coming out the holes between the shaft and
the case, reduce the rate of feed. That material can get in the bearings, and will wear the
bearings out. It’s recommend to run this mill wet, with
water. It takes about 1-2 US gallons per minute. Here’s a discharge chute coming out the
bottom. It’s reversible, so it can be bolted to this side as well. We’ll take a look down the inside of this
hammer mill. There are four rows of five hammers in this version, so there are 20 hammers total.
You can see our laser-cut screen here in the bottom, that’s a 0.8 millimeter slot. It
will produce material that’s 100% passing at 20-mesh, and 50%-60% passing a 50-mesh
screen. These hammers are high chrome content, so they’ll last, depending on the material,
if you’re running abrasive quartz, they’ll last somewhere between 1 to 2 weeks. They’re
reversible, so you can switch them around once this face is worn out. To change the
hammers, you take out the cauter pin, this pin slides out right over the bearing, you
can turn the hammers around and then replace the pin. These screens are welded in. To replace the
screen, there’s a weld along here, a skip weld in 1, 2, 3 places. Just grind it out
with a grinder, roll the new screen in, weld it up, and it should be good to go. It takes
about half an hour to do, and needs to be done every one to two hundred tons. This mill has replaceable armor all around
the bottom, bolted through to the outside of the base. To change the armor you take
out the bolts, knock that armor out, and then replace it with the new stuff and bolt it
back in. Here’s a look up into the hood. Same thing,
we have armor all the way around, top and bottom, and sides. It’s really easy to replace,
just take the bolts out, replace it with new armor, and bolt it back in. This machine needs to be greased here and
here, once a day, a couple pumps of grease in there to keep the bearings working properly.
Those are the only two greased fittings on this machine. Other things to check are the
belts, take the cover off every once in a while and check for tightness. Using this
jacking bolt here, the belt tension can be adjusted. So you loosen the motor mounts,
adjust the tension with this jacking screw here, and this one here. And when the belt’s
tight, and then retighten the motor mounts. When you first get the machine, run it for
a couple hours then shut down and check the tightness of the bolts and the belts. The
belts will stretch a little bit during the first couple hours of operation, and the bolts
may need to be tightened up again as well. We use nylock nuts so they shouldn’t come
loose, but it’s always better to check after the first couple hours and make sure everything’s
still tight. Here are a couple different sized screens
we use for the 16 x 12” hammer mill. This is a laser cut 0.8 millimeter screen like
you saw installed in the mill. This is great for miners because it produces a nice fine
grind. This is the next step up, this is about a 1.2 to 1.3 millimeters, and this screen
is also good for miners. It produces a little bit coarser grind, the throughput is increased,
so this screen will do about 2,500 pounds per hour. And we have an even larger screen
here, this is between 2 and 3 millimeters, it doesn’t grind as fine, but you get upwards
of two tons per hour out of this size screen. We’ve sold this coarser size screen to guys
who are re grinding metallic slag, and some of the soil-additive guys like a little bit
coarser grind. Some of the fertilizer guys and guys like that. So we’ve found some
good application for some of these coarser screens. So thanks for watching, and if you have any
questions for us about our hammer mills you can give us a call or e-mail us, all which
is in the description below. I’m interested to hear what you think of the mills, so give
us a call or email us, and we’ll catch you in the next video. Thanks for watching.


  1. This is pretty cool, the only thing that would make it easier is to use bolts for the screens instead of welding.

  2. Hi Tyler-
    Thanks for the comment about the bolt in screen.  We are working our way in that direction.  We have a bolt in screen for our recycling hammer mills (video coming soon) and it works great.  The reason we still weld in our mining screen is miners usually don't change to different screen sizes, they stick with one screen for the fineness of grind they need, when it wears out they replace it and keep going.  The other reason is it is hard to get a good tight tolerance all the way around the edges of the screen using a bolt in screen.  In the next six months we are going to try and make the switch to a bolt in screen for all our hammer mills.  Thanks again.


  4. Due to the big gap between the hammer and the screen if you throw in a "little" rock wont just fall down to the bottom of the screen and stay there forever? Thank for the video, very informative.

  5. Hi:
    I need a mill to be used to break and grind wet clay.
    The production should be 2 ton / hour and grind to a mesh of 35 U.S. STD. Sieve (0.5mm) size

  6. Hey where would I get screens for my hammer mill?

    I'm grinding transformers and electric motors. The bars I have suck!

  7. I love that machine, but do you know how the recycling center will take your glass. Will it be clean or (dirty) mix. Even if I just use clear bottles
    Thank you for your time.

  8. hi guys did you really said the hammers will last only 1 to 2 weeks.and were in Moçambique can we get supplies on backup parts

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