FAQs

Is a BlastBag plug the same as a gasbag?

Yes – MTI Group hold the trademark for the term BlastBag which is what we call the borehole product that is known commonly as the gasbag.

Why are there more models of BlastBag & BlastBag Solo plugs than there are for BlastBag Aero for the same range of hole sizes?

With BlastBag Aero plugs the operator controls the pressure that the bag inflates to, whereas BlastBag & BlastBag Solo plugs are inflated by an integral aerosol canister. Under certain conditions the wrong sized aerosol inflated borehole plug can burst or slip due to sub-optimal final inflation, hence to prevent this happening MTI Group have a number of standard sizes to cover the range of blast hole diameters commonly used in the mining industry. MTI Group also clearly indicates the size on the product so the shotfirer is assured of using the correct sized plug for the hole being loaded. BlastBag plugs for uncommon borehole diameters are available on application. 

Is HFC-134a a chlorofluorocarbon (CFC)?

No. Hydrofluorocarbons (HFCs) are composed entirely of carbon, hydrogen, and fluorine. They have no known effects at all on the ozone layer. Chlorofluorocarbons (CFC) are compounds containing chlorine, fluorine and carbon only, and contain no hydrogen. CFC’s were formerly used widely in industry, for example as refrigerants, propellants, and cleaning solvents. Their use has been regularly prohibited by the Montreal Protocol, because CFC’s are known ozone depleting substances (ODS). Only compounds containing chlorine and bromine are thought to harm the ozone layer – HFC-134a contains no chlorine and bromine. Fluorine itself is not ozone-toxic. However, HFCs can have the potential to contribute to global warming.

Apart from being the inflation medium for MTI Group BlastBags, what is HFC-134a used for?

In mining, non-flammable marking paint uses HFC-134a as a propellant. HFC-134a is widely used as the propellant in Ventolin® dispensers for the treatment of respiratory ailments, deodorant sprays, shaving creams and foams, marine safety horns, hornet & wasp sprays used on electrical equipment, dust blowers on electron microscopes and a variety of medical products other than metered dose inhalers (MDI).

What is the difference between BlastBag, BlastBag Aero & BlastBag Solo?

BlastBag plugs have a standard duck-bill deployment latch where BlastBag Solo plugs have our patented 2-speed push-latch deployment. BlastBag & BlastBag Solo plugs are inflated with an integral aerosol canister that is actuated and dropped into position in the borehole before it has fully inflated. After a prescribed period the BlastBag plug will have inflated sufficiently to be left to fully inflate without support. BlastBag Aero plug is inflated using an external source of compressed air. The plug is lowered down the hole on a hose deflated and fully inflated in situ. The design of the valve body allows decoupling once positioned & inflated. The Aero unit can also be deflated and repositioned if needed – a significant advantage over BlastBag & BlastBag Solo plugs.

What is an air deck?

An air deck is where a void is created in part of a borehole to achieve powder factor reduction and/or influence rock fragmentation. This is generally achieved with a BlastBag plug that is inflated in situ with compressed air or an aerosol propellant.

What are the main differences between a vane-type and turbine-type starter motor?

Vane starters are powered by a positive displacement air motor whereas turbine air starters use a rotodynamic air motor to convert air flow & pressure into motive power. Turbine air starters are generally quieter, lighter, less expensive to buy, have a simpler installation proposal (less components) for a given power output – for these reasons turbine air starters are immensely popular & substituting vane air starters in many applications.

What is tool condition monitoring?

Condition monitoring is a process where the maintenance costs are tracked over time to determine the life cycle costs (LCC) of a machine or tool. If over time the trend in maintenance costs increase above an acceptable level the option of replacement rather than repair may be a more cost-effective solution.

What is the conversion from cubic feet per minute (CFM) to liters per second (L/s) when considering flow rates?

Divide CFM by 2.12 to calculate L/sec
e.g. 100 CFM / 2.12 = 47.2 L/sec

What is the conversion from pounds per square inch (PSI) to kilopascals (KPA) when considering air pressure?

Multiply PSI by 6.9 to calculate KPA
e.g. 100 PSI x 6.9 = 690 KPA

Will HFC-134a (R134a) refrigerant gas be banned in Australia in 2010?

There is no impending or planned ban on HFC-134a (R134a) use in Australia or the rest of the world for that matter. In Europe (EU) new models of cars made after 1/1/2012 will have to use a lower global warning potential ( GWP) refrigerant because mobile air conditioning (MAC) is a big source of emissions due to nose to tail crashes and use of flexible hoses. All existing models, even new production, can still use R134a and the aftermarket for service of existing vehicles will still use R134a.
The world MAC industry looks as though in the future they will be going with HFO1234yf as a replacement product. Certainly the USA and Japan will be going the HFO route so the European’s will follow. It won’t however happen any time soon.
It is expected that when / if the carbon pollution reduction scheme (CPRS) comes into being in Australia it will make the R134a more expensive due to the carbon tax, but it will not be banned.
(Source: A-Gas (Australia) Pty Ltd, September 2009)