System Solutions for Mining and Tunnelling in Small Sized Tunnels
Mine operators are now increasingly calling for machines that are mobile, highly manoeuvrable, and capable of undertaking a wide range of roadway and tunnel drivage and reconstruction works.
When choosing a particular machine type, its degree of mechanisation has to be weighed up against the multipurpose nature of the deployment, which will then depend on the type of application and operating environment. While a “simple” all-hydraulic control system will not feature all the available sensor technology, and will have certain limitations when it comes to the automation of individual procedures, when compared to an all-automatic machine, it will be more robust under certain operating conditions, will require less maintenance effort, and will entail lower procurement costs.
Many manufacturers in India can supply crawler-mounted base vehicles in a number of weight categories, which can be equipped with different drive units, and can be supplied with or without quick- release attachments. The range of ancillary equipment available includes working platforms, drill feed, side-tipping shovels, and activated dinting shovels and special solutions such as cutting heads with airwater external spray systems and special shovels for laying curb stones.
Conventional equipment profile tunnelling for small-
Excavating small roadway and tunnel profiles using drilling and blasting methods, traditionally required manoeuvring hitches to be provided in the side-walls for materials transport, and to allow the different vehicles and items of equipment to pass each other, or be parked-ready for operation, as each process in the road heading cycle generally calls for a different machine with its own running gear. This means providing a large fleet of vehicles, resulting in high procurement and operating costs. Manoeuvring the individual machines into place takes time and further delays the sequence of operations.
Multifunction machines like the HBL 800 drill-loader (Fig1) have the potential to increase the rate of advance in that the main operations in the road heading cycle, namely drilling and loading, are combined in one carrier vehicle. This multipurpose machine is designed to operate on its own at the heading face. A drill feed attachment is fitted for shot hole drilling and roof bolting work (Fig 1), this being replaced by a sidetipping shovel (Figure 2) for the loading cycle. There is also the option of connecting a shot-crete manipulator. The installation is designed to operate in arch-profile tunnels with cross sections of 10 m2 and over. A twoto-one turnout and a preassembled section of track are also integrated into the system to serve as a floor-rail transport route. Other available attachments include telescopic drill feeds, a range of dinting shovels, hydraulic hammer drills, and various specialised tools for carrying out tunnel stabilisation work.
The HBL 800 drill-loader is equipped with electro-hydraulic drive and is operated from a driver’s cab with an overhead canopy to protect against falling stone. Using the machine as a stand-alone multifunction system for road head operations places higher stresses on the base vehicle when it comes to handling and servicing. However, procurement and operating costs are lower than for conventional machine systems, which comprise a drill jumbo and loader, as only the basic machine has to be purchased and serviced. Any maintenance work needed can be carried out during non-
Figure 1: HBL in position ready for drilling