M7 Table Troubleshooting
M7 Wave Table Troubleshooting:
SLANT: The heavier the ore the greater the slant. Extremely heavy ores require a slant of up to 5” or 6" at the top end of the Table. Very light ores require as little as 1" slant. The larger the mesh size of the ore, the greater the slant must be. If one had classified so that all particles are 1/4", the slant could be as much as 6".
WATER FLOW: The finer the mesh, the slower the water should flow. 1/4" particles might require as much as 20 gallons per minute, while 400 mesh particles might require as little as 5 gallons per minute.
TABLE MOTION (SPEED OF BUMPING ACTION): The bump speed should be approximately 300/minute. Note: higher and lower voltages raise and lower the bump speed. Adjust your table accordingly! The Table must move back and forth and bump at the head end of the Table. The distance traveled in each direction is about 1/2", but this can be more or less. The important factor is that the major portion of the ore on the Table remain in a fluid condition (as opposed to packing up). USE THE IMPACT ADJUSTMENT BOLT TO ADJUST THE MOTION. The heavier the ore, the harder the Table must impact at the head end.
To reiterate: another important point is the fact that the ore must stay fluid on the Table. In other words, the ore must not "pack up". Most ore will not pack up, but some heavy black sands will and when they do the Table must be adjusted for a stronger impact. The impact action of the Table is what prevents the ore from packing. If the ore starts to pack (not be fluid on the Table) then the impact action must be adjusted so that the impact is harder. Note: with a new table, the springs are tight and you might need to add 1 weight bar for extra impact action. A small amount of packing right against the riffle bar may not be bad, if the packed area is no thicker than 1". In order to prevent packing when one is processing extra heavy black sands, it may become necessary to mix white silica sand with the heavy black sands.
RE-CIRCULATING WATER: In many instances one may need to re-circulate the water. There is very little problem in this case. Very muddy water may be used, but one should not allow particles in the water larger than 1/10th the particle size being run on the Table. Thus re-circulation should be set up so that water has at least 1 hour settling time before it is re-circulated. With some ores, 10 minutes settling time is okay and some ores might require a good deal more time than 1 hour. Water with a lot of clay should be given more than 1 hour settling time. If your water does not settle out easily, ferric sulfate can be used to cause the particles to settle. Just sprinkle about 1 pound per hundred gallons of water. You can use more, but city waterworks use a great deal less with good results. It's not poisonous, but too much would be considered poisonous.
If it is possible, one should use clean water for concentrating the concentrates as clean water is needed to see the gold. Either use fresh water, or allow the particles to settle overnight before using to concentrate.
REPLACING FACTORY INSTALLED MOTOR: the following specs are to be followed: 1. 110 V AC 50 Hz Motor, 1425 RPM 2. Needed pulley ratio is 4.687 3. Weight pulley 9.93 4. Need motor pulley of 2.11 5. Variable pitch works best for variable voltages.
The M7 table factory installed motor is 1725 RPM @ 115 V AC 60 Hz with pulley ratio of 5.67 = 304 RPM (bumps per minute). You need to match the 304 RPM. The M8 table has a variable pulley installed so that you can adjust it to match these figures.
General troubleshoot points from Ian Freeland, Action Mining's Australia/Indonesia representative:
• The waves should form if the speed is around 287 to 320 RPM …or strokes per minute.
• If not…then check rpm of driven pulley with a tachometer.
• You may have a “brown out” giving slower motor speed.
• Bump should be a pronounced “bang” and approx stroke length of 10mm (3/8”).
• To get going….try to have a classified (screened to minus one mm (20 mesh) dummy sample of sand and gold ….and adjust the table tilt so that the back legs are initially about 80mm (3½”) high….so that the gold cons remain in a line across the deck….about half way between cons water spray bar and the feed hopper….which is about 100 - 150mm (4-6”) below the cons collection trough. Once you achieve this ….then slowly lower the legs by about 13mm (½”) at a time…to bring the gold cons into the collection trough/launder. Do not over feed M8 to begin with. Always, keep this dummy sample to test run the M8.
• Whenever the M8 is stopped…. When started again….you have to ‘fluff up’ the table material….to stop packing down.
• Make sure back legs have deck level across ways…using a spirit level.
Your Wave Table will operate optimally by:
• Having the WT firmly bolted down, preferably to a concrete slab
• Having it transversely, level
• Having motor running at correct speed….4 to 5 bumps per second
• Having the high end at correct tilt for the feed
• You can have 20 liters a minute of wash water in the feed box ok. But you do not have to have much coming out of the cons spray bar. Sometimes only a trickle is required from the cons spray bar…play with this a bit.
• Also you may have to drill an extra spray outlet hole at each end of the cons spray bar….so that spray water goes right to the edge of the deck. Just drill a 3/32” or 1/8” extra hole at each end.
• Have the water sprays from cons spray bar, slightly aiming down the deck (not just aimed directly, into the trough)
• Having correct ‘bump’ adjustment…and lock it so that it does not move through vibration.
• If WT bump plays up….while running, wind in clockwise the bump adjustment bolt until WT almost stops bumping…then wind out anti-clockwise to the correct bump. If you have bump too far anti-clockwise…the WT will stop bumping. So that is when you wind it in…then back it out again.
• CLASSIFYING your feed….no oversize trash competing against your finer gold particles
• Do not over -Feed …to begin with
• Try to feed steadily…reduce surges
• To begin….try to have the Cons line about 100mm (4”) down from the cons trough. Always achieve this prior to lowering tilt to produce a continuous cons discharge.
• Tighten up all grub screws as some come loose in transit
• Screw in Grease Nipples in each linear bearing and grease each 12 hours of running
• Just a few quick points above to try to help. Try not to change too many adjustments at the same time. Let WT settle down to an equilibrium ….a minute at least between adjustments ….as it takes time for WT to settle.
• Note that after each time the WT is stopped….one has to fluff up the deck residue….particularly run your ring finger under and along the leading edge of the nylon riffle bar….to ensure NO PACKING of feed pushed up against riffle bar. As gold will shoot over top of riffle bar…instead of having to go under.
• If you have a stuff –up….the simply re-run the tails back over the WT until you get it right.
• You should have plastic tubes/hoses coming off the tails and the cons outlets….each running into catch buckets. I use a bucket inside a bucket, inside another bucket for the cons. The largest of the 3 buckets has a water over flow hose at its top.
• Tails can go out many ways….I often use a length of open steel /gal guttering… to take tails away sideways from the WT…on a 10 degree minimum slope.
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