Long Hole Drilling - Production

Perseverance Drilling, Underground Pty Ltd has a range of Top Hammer rigs as shown in the Equipment List. These rigs can be utilised for production drilling, drilling long hole rises, sludge and probe drilling, drilling cable bolt holes as well as drilling with drilling foams and mud in bad / broken ground conditions.

With a range of long hole rigs in the fleet and a philosophy to always have a rig up our sleeve, there is normally a machine available to fill a client’s requirements. With a flexible workforce including a management team that all drill if required we are in a good position to move quickly if required.

Our Top hammer rigs drill holes from 51mm using a R32 drill string up to an 89mm hole using a T51 drill string, including everything in between. This allows us to complete work from thin vein mines to bulk mining operations. All of our rigs are capable of drilling both up holes and down holes and our operators are competent in both. All rigs have capabilities to drill on an air-water mist as well as drilling using drilling foams and muds.

We have extensive experience drilling in thin vein ore bodies, and have techniques, particular procedures and specific drilling consumables for thin vein drilling to achieve the accuracy required to drill out thin vein stopes. We have specific procedures for differing length holes which include techniques and consumables. We have developed our own guide system which has also improved accuracy.

We use our fleet of Simba H157’s to complete production drilling in thin vein orebodies. We have a range of rails that are available to suit some of the smallest drives. The Simba H157 is ideal for these situations as the rail without a carousel can be set up, very close to the hanging wall, which is especially important if you have developed the drives with a Shanti profile. You can see some examples of this in the Gallery.

We also have two systems that we can use to align the rail, our own Laser Clino for dumped holes, or a laser stick system if there is no dump on the holes. Both increase the accuracy over electronic systems as they ultimately rely on measuring the orientation of the actual guide tube, rather than the angle of the rail holder. In one particular case the client later told us that our drilling had produced half the tonnes at twice the grade than what they had budgeted on.

We also have a lot of experience in drilling in bulk mining situations. Again we have started to introduce the guide system that we have produced and are getting better accuracy results. For drilling in the larger bulk mining stopes, we can drill 64mm holes with a T38 drill string, 76mm holes with a T45 drill string or 89mm holes with a T51 string.

Whether part of a production drilling program, or sometimes as a single job, we are often required to drill Long Hole Rises. These can be slot rises or ventilation rises. In most situations we drill the blast holes as well as the reamers, however we have also been brought in to drill around existing raise drills to strip them out for a larger ventilation rise. When these raise drills exceed the optimum drill length of a long hole rig, we will drill them top and bottom. The up holes at the bottom of the rise will be fired, then the down holes around the top of the rise will be fired.

We have developed equipment and techniques using drilling foams and muds to drill in extremely broken ground. In the worst cases we may also resort to using cement grouts or gypsum. All of our rigs can be fitted with systems to use foams and mud. We have used these techniques for production drilling as well as drilling holes for cable bolts in broken ground. The technique uses the cuttings to form a crust around the circumference of the hole. With less fines removed from the surrounding rock and a crust formed, we have been able to make the holes in broken ground stand up until they are used.

When we have rigs on sites we often complete a number of tasks, rather than just Production drilling. These other jobs include drilling cable bolt holes and drilling service and probe holes. We have been required to do a lot of sludge drilling in the past, to a range of procedures, depending on the geologists requirements. From drilling holes and recording ore encountered in Nickel that will later have a probe used, to high level capture of all cuttings then sample splitting and chip sampling in Gold. We can tailor our procedure to suit a clients requirements.