BULK EMULSION IN UNDERGROUND MINING

Hi people around the world

I hope you and your family are safe.

I am working in a research about the application of bulk emulsion in underground mining, I read a lot of information about it and I hope you can help me with your opinions about its application in different mining methods and two question which are : 

What is the three best adavantages of this explosive ?

and

What is the best advance per blast that you obtained from its application?

 

Greetings from Peru and stay safe.

 

 

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  • Hi Tom

     

    Not related much to ANE (ammoium nitrate emulsion) use in UG - Harald provide most if not all the information for that type of technology. I just want to introduce you to a new bulk mining explosive technology -  in Australia we developed an explosive that was aimed to the coal market (open pit), which has had lots of problems with NOx fumes after blasting in the last couple of years. The explosive produces no NOx due to the lack of nitrogen in the molecule of the oxidiser (in other words, no ammonium nitrate or any other nitrate). The explosive has hydrogen peroxide instead, a commodity, as the main oxidiser material in the formulation. Trials have been conducted in quarries in Australia, but in 2017 a trial was conducted in the Sandvik research mine in Tampere (University of QUeensland, Forcit and Sandvik participated). No full faces were blasted, but only burn cuts. The HP-based product was compared against a commercial emulsion regarding the burn cut quality and gases produced. You can find the full report in this link

     

    https://geodocs.dmirs.wa.gov.au/Web/document/486738

    The product is still far away from commercialisation (open pit / UG) but it is important for all of us in the mining explosive industry to be aware of the new developments in the area.

    Kind regards

    Miguel Araos.

    GeoDocs
  • Equipment wise the cost of the emulsion loading ssytem is much more expensive and less realible than ANFO loaderts. A mobile ANFO loader with twin tanks can carry 1000 kgs of ANFO.

     

     

    • Hi Mr. Ernest

      The efectiveness of the ANFO is reduced when exist presence of water because it affect the results of the blast and the generation of noxius gases, and about the capacity to move the Bulk emulsion, you can move more than 1000 kg with one loading equipment, one example that I can mention is the Factory Assembly UBT from Enaex, which has the capacity to move 1400 Kg of emulsion. 

      About the cost, in different cases around the world the application of this explosive generate savings in different operations like drilling, hauling, transportation, ventilation, crushing, etc; and this is because the properties of the bulk emulsion give you better results in terms of advances, fragmentation, low level of noxious gases, etc than ANFO properties.

      Apart from that is necesary to have a good planification of your operation with the bulk emulsion, because the savings that it can generates will pay the necesary investment cost and give you more incomes, but to achieve this is necesary to take advantage of all of the properties of the bulk emulsion explosives.

      Regards

  • High loading speed

    Bulk emulsions are loaded into blastholes at similar rates to ANFO. However, because the emulsion is pumped from storage into the loading unit rather than by accessing bags of explosives from magazines, the overall process is much faster than an ANFO based system. Generally, the emulsion hopper on the loading unit is sized to enable a full shift of loading without replenishment. ANFO pressure kettle based systems cannot match this.

    Emulsion water resistance

    Emulsions are highly water resistant resulting in improved  detonation reliability versus ANFO. Outputs include improved overall fragmentation, less misfires and less toxic fumes.

    Low levels of noxious fume

    ·       Theoretically, the detonation of ANFO and emulsion explosives results in complete combustion and low fume levels. However, ANFO is readily affected by water and can produce copious volumes of noxious gases. The water resistance of emulsions results in improved detonation characteristics in damp or wet conditions and potential to re enter workplaces earlier than for ANFO blasts. Mines should assume that noxious gasses will be present with all explosives and test air quality to verify re- entry standards are met.

     

    Ease of storage and transfer

    ·       Emulsions are easily transported, transferred into storage and later recovered for use by pumping. This feature reduces manual handling, provides high rates of transfer and also allows ease of stock control. Mines require less personnel to manage stock and can reduce the size and risk of underground magazines. Miner occupational health is at lower risk  through a reduced need to lift and transport bags of ANFO or boxes of emulsion.

     

    Emulsions sensitized at point of use

    ·       Underground emulsions are sensitized as they are being pumped thereby reducing the storage of pre- sensitized explosives. This has positive security and safety benefits for mines.

    Low nitrate contamination

    ·       The water resistance of emulsions results in lower nitrate contamination in mine water versus ANFO explosive. Nitrates are highly soluble in water and spillage of ANFO underground invariably results in contamination of mine effluent. Emulsions are highly insoluble making them relatively easy to collect and dispose of by acceptable means

    Single density

    ·       While this system only permits the loading of a single density product the energy at this density is lower than for blow loaded ANFO. Development headings are blasted at much higher energies than desirable and emulsion allows the customer to partially address this problem.

    Improved stock control

    ·       Bulk emulsions can reduce the number of different explosives required and can eliminate packaged lifter products in development mining. The need for stock rotation in magazines and waste due to poor magazine control can be reduced. As a consequence, misfires caused by use of out of date stock can be reduced.

    Unused emulsion not wasted

    ·       When ANFO blasts are completed, miners often dump the remaining ANFO to prevent it blocking the pressure loader. This is an environmental and cost issue. Emulsions, if not used can remain in the loader, unsensitised, or they can be returned to storage if an extended delay in loading is expected.

    Reduced ammonia fume

    ·       Ammonia fume is often an issue when ANFO is used in areas where cement paste is present. Emulsions have less free AN available for reaction with cement paste and have been demonstrated to reduce ammonia levels in these types of situations.

    Improved advance rates

    ·       In many instances the use of emulsion can improve the percentage of round pull versus ANFO. A 200mm improvement per round, for example, can have a substantial impact on mining cost per metre and on project completion date. An increase in pull of 200mm per round could result in a cost benefit that is greater than the cost of explosives used.

    Elimination of pressure loaders

    ·       ANFO pressure loaders are a pressure vessel and must be tested and licensed at regular intervals

    Reduced static electricity hazard

    ·       Bulk emulsions do not generate static electricity and don’t require anti static hoses, a cost and safety benefit

     

     

    • Like always....one of the best in the Industry Harald well done.Nothing I could even add.👍

    • Hi Chris, thanks!. I got tought well at Orica and have done and seen it.

    • very good and breif explanation Harald.

      Regards.

       

    • Hi Harald

      Thanks for your complete answer, I agree with you on all the information and I have another question for you:

      What do you think about the application of bulk pumpable emulsion with the use of boosters and electronic detonators?, What advantages can you improve more with this combination of explosives products?

       

      Regards

    • Hi Tom, 

      Boosters you might have to use in longhole blastholes. But this is theory. In practise this is easily said than done and I haven't seen crews doing this for practical reasons.  Electronic detonators might help you in various ways such as vibration control, fragmentation, increase size of blast etc. etc.

  • Dear Tom

    I had a few chance to use the bulk emulsion in the U/G mines.

    Advantages: it is an automatic application (easy to use), can charge the holes %100, you can change the density during the charging operation (controll the energy for different area at the face), 

    Best advance: 4m hole in an Iron mine blasted and full advance (4 m) we got.

    Regards.

     

    Umit

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