Technical Resource
ANFO vs Emulsion
The handling split plants use: dry ANFO or pumpable emulsion matrix, and which stainless NAPCO pumps belong on the fluid side.
ANFO is dry ammonium nitrate prill mixed with fuel oil. It is poured or blown. Emulsion is a water-in-oil ammonium nitrate matrix, and it stays a fluid until it is sensitized or packaged. Only the emulsion side is a pumping job. NAPCO does not make blasting agents. We build stainless rotary gear pumps for surface and plant transfer of unsensitized bulk matrix, AN solution, and high-emulsion Heavy ANFO. Start at explosives and mining, then PA300S or PA200S.
If you came here to pick a blasting agent, talk to your explosives supplier. If you came here because a plant or truck has to move one of these products, stay long enough to get the handling right.
Straight ANFO
Straight ANFO is porous ammonium nitrate prill plus about 6% fuel oil. It is dry. It flows like grain. It has no water resistance.
It is cheap, and it is still the default on a dry hole when the rock wants heave more than shock.
You do not pump it. You pour it or blow it. See pumping ammonium nitrate emulsion and ANFO: straight ANFO stays on augers or compressed air, never on a gear pump.
The liquid on an ANFO pad is usually the fuel oil that coats the prill. That circuit is petroleum transfer, not ammonium nitrate transfer. See gear pumps for fuel and petroleum.
Emulsion
A bulk emulsion is concentrated ammonium nitrate solution dispersed in a fuel-oil phase. An emulsifier holds the interface. The matrix looks more like grease than like a thin liquid.
Until it is sensitized, unsensitized matrix is typically handled as an oxidizer, not as a Class 1 explosive. Bulk emulsion products lists that state as UN3375, Class 5.1. Sensitization (gassing at the hole, or microballoons in packaged product) is what turns it into a blasting agent.
That is why mines run bulk emulsion on wet ground, and why a plant has a real pumping job. The matrix is a fluid. It has to move tank to tank, silo to truck, truck to reload.
Packaged / cartridge emulsion is the other emulsion form. It is plant-sensitized and loaded by hand. It is not pumped. That page is cartridge emulsion explosives.
Heavy ANFO sits in the middle
Heavy ANFO is emulsion matrix blended with ANFO prill. The usual range is 20% to 70% emulsion by weight.
Adding emulsion coats the prill, raises density, and starts to give the column water resistance. Adding more emulsion improves those traits and raises cost. High-emulsion mixes can still move through a gear pump. High-prill mixes are augered.
Do not spec a pump off the name. Spec it off the blend and the product TDS.
Site-mixed emulsion and repumpable matrix are logistics variants of the emulsion side, not a third blasting agent. Details live on bulk emulsion products.
What you can pump
Four products get mixed together in search. The handling is not interchangeable.
- Straight ANFO: dry prill plus fuel oil. Augered or blown. Never pumped.
- Cartridge emulsion: packaged and plant-sensitized. Hand loaded. No transfer pump.
- Heavy ANFO: blend-dependent. High-emulsion mixes move through a gear pump. High-prill mixes are augered. Confirm with the product TDS.
- Bulk emulsion matrix and hot AN solution: pumpable. Stainless gear pump, surface and plant transfer, low shaft speed.
Stay on stainless. Ammonium nitrate corrodes iron. Comparison: stainless steel vs ductile iron pumps.
Shear matters. The emulsifier holds the oil-water interface. High-speed impellers tear it. Gear pumps move a fixed volume between teeth at low shaft speed. Working principle: rotary gear pump working principle.
NAPCO pumps are surface transfer: tank to tank, plant to truck, silo to reload. Not borehole injection of already-gassed product. That high-pressure loading job is progressive cavity duty. See gear pumps vs progressive cavity pumps.
Selection logic for the bulk side: pump selection for emulsion explosives and gear pumps for bulk emulsion trucks.
Which stainless pump, if the product is a fluid
Specs below are from the live product pages, Rev. 07/2026. Water tables. Higher-viscosity fluids may require lower RPM. Do not invent an ANFO flow rate. There isn’t one.
PA300S
The PA300S is the 3-inch stainless pump. 158 GPM at 280 RPM and 10 PSI. 140 GPM at 100 PSI. 13.4 brake HP at 100 PSI. Max 100 PSI, max 280 RPM, 173 lbs. 3-inch NPT.
Plant pump-over, truck loading, high-volume matrix transfer.
Rebuild kit: PK300S. 2 to 5 hours with hand tools. Surface and plant transfer only.
PA200S
The PA200S is the 2-inch stainless pump. 69 GPM at 190 RPM and 10 PSI. 60 GPM at 100 PSI. 5.7 brake HP at 100 PSI. Max 100 PSI, max 190 RPM, 114 lbs. 2-inch NPT.
Skids, smaller batch plants, auxiliary circuits where the 3-inch pump is oversized.
Rebuild kit: PK200S. 2 to 4 hours with hand tools.
Both sizes prime themselves and run either direction. Nitrile gears are standard. Viton gears are the option for hot AN solution or aggressive formulations. Viton seals are already on every NAPCO pump. Gear choice: nitrile vs Viton gears.
Rebuild
Each stainless kit carries the drive and idler gear assemblies, four roller bearings, high- and low-pressure seals, the centercase gasket set, and 4 × PB43 cover bolt o-rings. Kits do not include the housing, end covers, wear plates, or assembly lubricant. PK300S rebuilds the PA300S. PK200S rebuilds the PA200S. A rebuild runs about 30 to 50 percent less than a new pump. Every kit: service kits.
Jobs this page is not
- Selling ANFO, emulsion, packaged boosters, or detonators.
- Specifying a pump to move dry prill.
- High-pressure downhole loading of gassed product.
- Specifying anything but stainless on an ammonium nitrate circuit.
If you still need to size flow and pressure from viscosity, use how to size a rotary gear pump.
FAQ
What is the difference between ANFO and emulsion?
ANFO is dry prill plus fuel oil. Emulsion is a water-in-oil ammonium nitrate matrix. ANFO is poured or blown. Emulsion is a pumpable fluid until you choose to gas it or pack it.
Can you pump ANFO?
Straight ANFO, no. Heavy ANFO with a high emulsion fraction, sometimes. Confirm the blend with the product TDS before you order a pump.
Can you pump emulsion?
Unsensitized bulk matrix and hot AN solution, yes: stainless gear pump, surface transfer. Cartridge emulsion, no. Already-gassed product down a blast hole is not a NAPCO gear-pump job.
Does NAPCO make ANFO or emulsion?
No. NAPCO manufactures stainless rotary gear pumps for bulk matrix and AN solution transfer.
Why stainless?
Ammonium nitrate corrodes iron. Stainless housings and shafts are the wetted materials for any AN or emulsion circuit.
Is ANFO vs emulsion a pumping decision?
Only on the emulsion side. Straight ANFO is poured or blown, never pumped. Unsensitized emulsion matrix, AN solution, and high-emulsion blends are pumped. Confirm the blend with the product TDS before you order a pump.
What pump moves emulsion matrix at a plant?
A stainless rotary gear pump at low shaft speed. PA300S for plant pump-over and truck loading. PA200S for skids, smaller batch plants, and auxiliary circuits. Surface and plant transfer only. Start at explosives and mining.
Which repair kit rebuilds a stainless emulsion pump?
PK300S rebuilds the PA300S in 2 to 5 hours. PK200S rebuilds the PA200S in 2 to 4 hours. Each kit includes both gear assemblies, four roller bearings, high- and low-pressure seals, the centercase gasket set, and 4 × PB43 cover bolt o-rings. It does not include the housing, end covers, wear plates, or assembly lubricant.
If you actually need to transfer bulk matrix
Send the product type (matrix, AN solution, or blend), flow rate, pressure, and temperature. We will confirm whether the grade is pumpable and which stainless pump and kit belong on the skid.