New DTi Jumbo Series from Sandvik

Sandvik has unveiled its new tunnelling jumbo series, initially intended for selected markets in Europe, North and South America and the Far East. The DTi series tunnelling jumbos embrace 4 different models for driving operations with a cross-section ranging from 16 to 203  m², for face drilling, anchor drilling and mechanised long hole drilling. All models belonging to the DTi series are distinguished by their speed, precision and user-friendliness and provide convincing driving results given a favourable cost-ratio. They combine precision and power with numerous practi-cal and intelligent functions (Fig. 1).
Thanks to the i-series Sandvik has been able to set new standards in tunnelling. According to Jorma Kalliomäki, Market and Offering Manager of Sandvik’s Tunnelling and Underground Civil Engineering division, the new series represents the crowning achievement of 50 years’ experience, research and development in drilling technology at Sandvik Mining & Construction.
Ultra-modern technology combined with solutions for current customer requirements with regard to precision, speed and user-friendliness form the basis for the entire product series. The DTi tunnelling jumbos include production data collection and data accumulation on rounds, cumulative product data and drilling parameters among their intelligent functions. These data can be used for production logistics planning, regular service operations and improving performance.
The DTi series are intended to operate in automatic mode. They work exactly in accordance with the scheduled drilling plan and the prescribed drilling sequence, something which is to the advantage of safe planning of tunnelling progress. There are numerous functions, by means of which the operator can finely attune the drilling process to ensure additional flexibility, which is required for certain rock formations. With the help of the Lock-to-Target function he can rapidly find the correct drilling position, whereas he is capable of influencing the individual drilling stages thanks to QuickStep. The Dynamic-Correct function constantly aligns the drilling direction whilst the drilling booms are moving. In this way the determined drilling depth is adhered to. In addition the jumbo operator has the possibility of adjusting the drilling power steering, feed and rotation speed (Fig. 2).
Apart from precision the DTi series is distinguished by the boom control. This is based on the proven deflection compensation but has been expanded by the introduction of new features: a compensation model to position the drilling booms and the Roll-Over joint.
A new front drill steel guidance is numbered among the improved precision features, which assures the guidance of the drill steel in the collaring phase. In addition the drill bit remains inside the front guide so that it can get as close to the rock as possible without being deflected. 
The DTi jumbos make use of Sandvik iSure tunnel planning software. This software affords new and efficient possibilities of working simultaneously with the drilling and blasting pattern. The main advantage of the software is that it takes the position of the very bottom of the hole – where driving operations are at their most sophisticated and the greatest amount of energy is required for breaking and removing the rock – in order to calculate the hole spacing and direction. iSure assures optimised blasting according to plan, supplies better pull-out, decreased need for scaling, better loadability and smoother collaring in the following round. These aspects contribute to high driving quality and ensure that the tunnelling project can be concluded within the shortest possible time. The economic advantages for the contractor are obvious when faster tunnelling progress and the reduction of overbreak and in turn lower costs thanks to the lower requirements of concrete formwork are taken into consideration.
The iSure software also offers an overview of the actual drilling process as data relating to round, operator, service and overall performance can be evaluated. The results can be presented either numerically or graphically. In addition the iSure software provides visual 3D and diagram presentations of various, important drilling parameters and offers a MWD (Measure-ment while Drilling) tool to monitor the driving process and the rock development.
Both the i-series jumbos as well as the iSure software offer the opportunity to determine the given drilling parameters for different types of holes. Thanks to this function, the performance is reduced for contour holes, for which utmost accuracy is particularly significant and the initial drilling phase extended. At the same time, the performance for field holes is increased thus reducing the drilling time without this having a negative outcome on the profile quality (Fig. 3).
A further special possibility for increasing precision is advanced factory calibration especially suitable for site conditions. In this way accuracy can be maintained simply and without any problems.
Good working conditions and high safety were just some of the major aspects considered in developing the Sandvik DTi tunnelling jumbo series. The modern, FOPS-certified cab, which now has a more than 20  % greater window area, offers sufficient room and unrestricted visibility for all drilling applications even if the cab is not elevated. The operator’s seat is positioned directly in front of the windshield and the cab is provided with high-performance xenon headlights for drilling and tramming. The all-round impression is one of being user-friendly. The control system is integrated in the armrests, the surrounding air is filtered and the air flow optimised. Thanks to the good noise suppression and vibration control working with the DTi jumbos is considerably enhanced.
The construction of the DTi series is geared to ease of service. The components requiring daily maintenance are thus damage-protected and can be easily reached from ground level. The fact that the rock drill modules can be serviced from the feed beam and all boom hoses are ingeniously integrated contributes to the straightforward servicing.
The machines’ functions also include status monitoring as well as an integrated self-diagnosis system. This embraces an onboard diagnosis on the operator display as well as a graphic presentation of components and sub-system status as well as concise and straightforward means of tracing faults. All incidents in the control system are stored for subsequent analysis purposes.
The DTi tunnelling jumbo series machines can be configured with many different functions and components and thus can be adapted for various requirements in tunnelling as well as for different rock formations.