Technical

ANFO Loader Technical Information

How to Operate an ANFO Loader

Our ANFO loaders are shipped fully assembled and ready to use upon arrival.

  1. Connect to a compressed air supply. Types PA, PB and PC ejector elements are designed for best performance at 80 PSI, but they will operate satisfactorily in the range of 60-120 PSI. It is suggested that the Loader be connected to the rock drill air hose with two feet or more of ½” air hose to facilitate handling the loader.
  2. Connect an approved anti-static loading hose of the appropriate size to the Ejector Element.
    • PA Element – 5/8” I.D. hose.
    • PB Element – ¾” I.D hose
    • PC Element – 1” I.D. hose
  3. A grounding lug with wing nuts is provided on the Loader and should be used to ground the Loader through a wire connected to a rock bolt or other reliable ground.
  4. Having connected the air line, loading hose and static wire, open the compressed air valve
  5. Test the remote-control valve action by activating the remote-control valve several times. With the standard seven-foot control hose the valve action should be instantaneous. With a longer control hose a slight delay in shutting off is normal.
  6. Empty a bag of ANFO into the hopper. To load the hole, insert the anti-static loading hose to the full depth of the hole and retract about a foot. Depress the control valve lever and the Loader will operate. As the hole fills up, the loading hose must be slowly retracted to avoid blowing the ANFO out of the hole.

Safety

Any pneumatic loading device may produce static electricity by frictional action of the ANFO and air moving through the loader and loading hose. To protect personnel from electrical shocks and premature clasts, an anti-static loading hose should be used and the Loader should be electrically grounded. In some areas, the local mining regulations forbid blowing of ANFO into bore holes bottom-primed with electrical detonators. In other areas, this is permitted after safety checks. Before proceeding, contact your local Department of Mines.

Local Safety regulations should be followed at all times.

Safety glasses and gloves should be worn when loading, and the operator should stand to one side to avoid being struck by air-borne particles.

Care of the Loader

After use, the excess blasting agent should be emptied from the Loader. The loader should then be operated for a few seconds to clear the ejector and hose of the ANFO. Invert the loader when not in use so that moisture, rock and other substrates will not collect in the Hopper. The ejector assembly should be taken apart occasionally and cleaned with light mineral spirits. Blow dry with an air gun.

Disassembly

  1. Ejector Element: To disassemble the ejector element (41P), unscrew the element retaining nut (39P) (diagram 1) The Ejector Element can then be removed from the body along with the O-Ring Seal (44P)
  2. Body Valve: Remove the four screws (37P) (diagram 2). The body valve cover (36P) will then come off along with the rubber Body Disc (34P) and the Body Disc Insert (35P). The Body Screen (33P) can be pulled out, with a pair of needle-nose pliers if necessary. The Body Screen Holder (32P) does not be to be removed.

Assembly

The valve assembly goes together in the reverse order from which it was taken apart. When replacing the Ejector Element in the body, check the O-Ring Seal to confirm that it is free of nuts. All parts must be cleaned before reassembly.

Loading Rates and Capacities

Three types of Ejector Elements are available:

  • PA for 5/8” hose and 1-1/8” holes. Recommended maximum hose length – 25 feet.
  • PB for ¾” I.D. hose and 1 ¼ – 1 3/8” holes. Recommended maximum hose length – 30 feet.
  • PC for 1” I.D. hose and holes 1 ½ and larger. Recommended maximum hose length – 40 feet.

Longer hoses can be used, but it may compromise loading speeds.

Troubleshooting

If satisfactory performance is not obtained, the following points should be examined:

  • Check for damage to the O-Ring real (44P). When the Ejector Element (41P) is removed, it should be replaced with reasonable care, being careful not to damage the O-ring. Damage to the O-ring will result in low vacuum or no vacuum.
  • The air line oiler should be disconnected when using the Loader.
  • Regardless of the drill-hole size, the proper size hose must be used with each ejector element.
    • PA Element – 5/8” I.D. hose
    • PB Element – ¾” I.D hose
    • PC Element – 1’ I.D. hose

Larger hoses than indicated may reduce the density of the loaded ANFO. Smaller hoses than indicated will reduce the loading rate. This is especially true for the PC element.

Lower vacuum than the amount shown in the table below maybe be caused by one of the following:

Element Vacuum
  Ins. Hg. mm. Hg.
PA 15-18 380-460
PB 14-18 350-460
PC 12-16 300-400
Problem observed Possible reason/solution
Air pressure too low or too high. Check PSI gauge.
Dirty ejector element. Examine bore of element for a deposit of caked ANFO.
Remove element from body and clean peripheral orifice, using a piece of ,010 in. shim cut to a point, and inserting from the discharge end of the element to loosen bits of rock, etc., which may clog the orifice.
Damaged 0-ring seal (44P) on Ejector Element. Replace if necessary.
Dirty Body Screen (33P). Remove and clean as per operat­ing instructions.

If none of the above faults exist and the vacuum is still low, put a new element into the loader, and if the low vacuum is not corrected then the vacuum gauge and rubber stopper assembly may be faulty. Please contact us to order replacement parts.