The Atelier Val-d’Or VD8000 drill rig
A proven solution for deep hole surface drilling
With years of use behind them, Atelier Val-d’Or’s VD8000 and its smaller sibling the VD5000 have shown that they have what it takes to tackle the most demanding surface coring jobs in a safe and efficient manner.
The VD8000 was designed primarily for work in cold climates, built inside a closed shack mounted on skids with the option of insulated walls and heated floors, but the shade afforded in hot climates has proved welcome in comparison with other surface rigs.
It comes with AVD’s rod-handling system as standard, with a stacking capacity of more than 8,000 feet (2,500 metres*) of ‘N’ rods in a parallel folding modular rod rack. Users have a choice of a 10-foot (3 metre) or 11-foot (3.3 metre) feed frame with over 55,000 lbs (25,000 kg) pull back. The 3.3-metre frame allows for top drive drilling with full 3-metre casings. There is also the possibility of accommodating a user’s preference in diesel engines, with options including Cummins, John Deere and CAT among others.
The VD8000 offers many features and options which make operations safer.
- The main hydraulic components can be accessed from the outside, keeping technicians away from moving parts.
- An interlock guard system is available, completely separating the operators from moving parts, and cutting power to the drill head if a guard door is opened during drilling.
- The drill mast’s extension and rod slide can be locked in place remotely from the drill floor, reducing the use of ladders.
- A casing breaker and casing clamp are available, eliminating the needs for tools to break casing string joints.
AVD drills are fully hydraulic, but soon users of new or existing drills will have the option of switching the main functions to electro-hydraulic controls. This optional package will raise the efficiency and safety of drilling operations for a minimum investment, and in the case of existing drills can be implemented in a few hours. If necessary, the controls can be switched back to fully hydraulic in less than an hour.
This modular package allows the operator to add ‘plug-and-play’ options. The basic module consists of two joysticks and a 7” display. The screen gives instant feedback on parameters such as true spindle speed, feed and rotation pressure.
The module also allows the saving of local sensor data every second to a USB flash drive. The Danfoss IP67-rated controller offers additional sophistications such as a synch function with automatic preloading for deep hole drilling, one-handed tripping operations and automatic wireline winch rewinding for safe overshot retrieval. It will also prevent costly operational mistakes through a combination of sensors and software rules. One optional add-on is the Danfoss Telematics, which uses a cell phone connection for remote data acquisition, real time diagnostics and intervention. A drill head position sensor is also available, allowing for feed rate measurement, automatic feed cylinder cushioning, and shift/day drilled meters feedback. This information is automatically added to the list of parameters recorded by USB drive or Telematics, the data acquisition system.
Automatic preloading for deep hole drilling
When tripping rods, the load of the rod string on the chuck or the rod clamp makes them stretch and settle in their seats. It also puts a load on the feed cylinder (over 4,000 PSI on deep holes). In shallow holes, the effect is negligible, but as operators drill deeper and deeper, the components will take a hit if the load is transferred too suddenly.
For example, 2,000 metres on ‘N’ rods weigh roughly 15,000 kg with the chuck holding the string. If the rod clamp is closed on the rod string, the chuck then opened, all the weight of the rod string will suddenly transfer to the rod clamp, forcing it to stretch and settle in a fraction of a second. As a result, the chuck, drill head and feed cylinder will bounce back from the rapid load release.
Experienced deep hole drillers will keep both chuck and rod clamp closed and slightly push or pull with the feed cylinder to preload the chuck and rod clamp, but this is not an exact science. With AVD’s controller and sensors installed, the system is aware if the chuck or rod clamp are open or closed, and the feed cylinder pressure with the chuck holding the rod string. It can then properly preload the chuck and rod clamp before allowing either of them to open. This feature automatically activates when the feed cylinder pressure goes beyond a pre-set value.
One-handed tripping operation
The one-handed tripping feature, for example, takes some of the risk out of repetitive tasks like tripping rods up and down to change a drill bit. The operator needs to tell the system if he is tripping in or out, then use one joystick to make the drill head go up or down. The system will take care of deciding if the chuck or the rod clamp should be opened and will also do the preload sequence if necessary. If equipped with the optional head position sensor, the system will also manage to keep the pulling stroke constant (3m or 10 ft.) to keep the rod joints at the same position along the tripping operations.
Automatic wireline winch rewinding
With automatic wireline winch rewinding, the operator resets a winch counter on the system before manually sending the overshot down. The system counts the number of turns made by the winch drum when going down. When the operator is ready to rewind the winch, he activates the feature and the system rewinds until a pre-set number of turns are left before reaching the surface. Rewinding then slows down and the unit beeps continuously before stopping completely. The operator can then finish rewinding manually and bring the core sample up to the surface.
In an effort to satisfy the needs of specific exploration sectors, such as crossing a thick overburden layer with large casing, coal exploration, or the need for large samples in the search for diamonds, AVD will soon start field testing its new ‘S’ class line of products.
Designed as a drop-in replacement for existing AVD ‘H’ or ‘P’ drill heads, chucks and rod clamps, the new ‘S’ components will let operators work ‘through the spindle’ with rods and tools up to 5-1/2 inches in diameter. To safely handle the heavier pipes, a new universal rod handler able to take from ‘B’ to ‘S’ rods will also be made available.
The VD8000 can be customized for a user’s specific needs. Customisations include an optional ground pick-up rod handler to grab rods from a sloop besides the drill, additional hydraulic outputs and controls to power an external mud system, wheels for open-pit operations and so on.
Atelier Val-d’Or is based in Québec, Canada. It has more than 30 years of experience in the design and manufacture of exploration drilling equipment for the mining industry. Clients include Major Drilling, Foraco and Norex Drilling. AVD has built over 200 drill rigs since entering the market in the mid 80s, and rigs have seen in service in Canada, USA, Mexico, Brazil, Chile, Argentina, Suriname, Colombia, Philippines, Ireland, Ghana, Burkina Faso and Azerbaijan. AVD is best known for its quality, deep-drilling rigs, its fast and reliable rod-handling systems and custom-made solutions. For more information, please visit http://www.ateliervd.qc.ca/or facebook.com/ateliervd
*AVD does not give hole depth specifications or make claims because engineering certification relates to the weight the system can support, which does not easily translate into depth because of the many other factors involved – the inclination of the borehole, the type of rock being drilled, wedges or directional drilling used, presence of water in the hole, and so on. Anecdotally, the VD8000 has on many occasions drilled to 3,000-plus metres using thin-walled ‘N’ rods.