Focus of the paper
This technical paper condenses the development of a purpose-built linear cutting machine, its application to UG2 reef and the calibration of a finite-element cutting model. The central engineering problem is that UG2 is both hard and highly heterogeneous: rock strength can change over very short distances, making force response and fragmentation harder to predict than in a uniform reference material.
Machine development and experiments
The machine was first commissioned on sandstone and then used to conduct controlled cutting tests on UG2 with a conical pick. Tests varied cutting depth, spacing and pick geometry while measuring normal and drag forces. The sandstone programme provided a stable reference against which the more irregular UG2 response could be interpreted.
Negative skew angles generally increased the measured forces. At a 4 mm cutting depth, forces tended to plateau once the spacing-to-depth ratio reached approximately four or more, while the shallower 2 mm tests behaved differently. The most striking practical observation was the persistence of fine, powder-like UG2 fragments, even where deeper sandstone cuts produced larger chips.
Numerical model
The experiments were used to calibrate an ANSYS LS-DYNA continuous surface cap model. A tetrahedral rock mesh and a modelled cutting tool reproduced a selected operating condition reasonably well after calibration. The balance between peak and mean response could be represented, but the normal-to-drag force relationship remained imperfect and accuracy deteriorated when the cutting depth changed.
The model should therefore be read as a calibrated representation rather than a universal UG2 cutting law. Further material-model development and validation across a wider test matrix are needed before it can be used confidently to optimise machinery.
Contribution and limitations
The paper brings experimental hardware, material testing and simulation into one repeatable workflow for a rock type that had received little conical-pick cutting research. It also prevents an overly simple conclusion: demonstrating that UG2 can be cut in the laboratory does not by itself demonstrate a viable mining system. Fragment size, stope cleaning and model transferability remain decisive constraints.
Future work should broaden the operating envelope, improve the generality of the numerical model and investigate methods for managing fine cuttings. Those steps would turn the present calibrated experiments into stronger evidence for machine and process design.