Engineering & Mining Journal

APR 2018

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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Page 64 of 91

UNDERGROUND MINING APRIL 2018 • E&MJ 63 Reduce shovel hang time Virtually eliminate re-spotting Equalize operator capability & performance Building tomorrow's technologies for today's mines GUIDED SPOTTING GET RIGHT TO THE SPOT CIM Booth 940 UP TO 34 % INCREASE IN SHOVEL PRODUCTIVITY *achieved at customer site They stipulate that the employer must take reasonable prac- tical measures to ensure that people are not injured as a result of brake failure. These include ensuring that TMMs are operated with adequate and effective braking systems; and that all brak- ing systems are adequately and routinely tested for intended functionality and are regularly maintained. Where a combined braking system is used, it needs to comply with the require- ments for the separate systems and be fail-safe. Meanwhile, the mandatory code of practice stipulates that conformity of production (COP) must describe the procedures for testing of braking systems to ensure functionality, in terms of brake-design specifications. This is relevant for static testing, dynamic-type or other testing methods for the recording and safe keeping of test results for a period specified by the COP. The code also mandates the provision of brake descriptions, as well as the test procedures. These need to be supplied in ta- ble format. Accumulator systems need to be tested for a number of applications and hold time. SANS/ISO3450 is the standard by which testing of surface op- erated equipment is undertaken. However, Burger highlights that there are also glaring pitfalls in the standard ramp-testing sys- tem used to test the braking systems of large-surface mining ma- chines. Many of the ramps for testing purposes have been built at incorrect angles, despite the SANS 1589 also specifying that they must be at least 4° steeper than the steepest gradient at a mine. The correct ramp procedures are also seldom followed in the test- ing of the service and neutral brake. Standards are also not adhered to in the testing of the park/emergen- cy brake. Here, the test needs to be un- dertaken while the engine is off and the vehicle without an operator to ensure that the inspection is not being aided by the service brake. Meanwhile, the very accurate values in the gradient hold test stipulated by ISO3450 are seldom in line with the OEM's specifi- cations. For example, the service and park/emergency brake-test- ing specifications for a 100-mt rigid-dump truck are to be under- taken at 20% and 15% slope gradients, respectively. However, some OEMs specify that testing of park brakes need to be un- dertaken on gradients of up to 15%. This means that the vehicle cannot be tested according to the standard as it will fail and even result in costly warranty-related issues with the manufacturer. CMTI has developed the SBT500 slab-brake tester for vehi- cles exceeding 50 mt. This allows the vehicle to be tested on a moving platform that is hydraulically actuated and equipped with the necessary load cells to record the testing data. (Slamming the Brakes on Sub-standard Testing - from p. 61) All tests are photographed and a comprehensive report, including a time and date stamp, is generated for every test.

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