Hoisting system requirements

The higher elastic stretch of aramid ropes, up to 30% for equivalent payload, may require taller headframe height to allow for the difference in stretch between loaded and empty conveyances. It is a fact that most probably the design of hoisting systems, including the headframe and ancillary services, will required a novel approach and most probably as well will result in a CAPEX saving ... 

This paper focuses on electrical losses and total efficiencies of two alternative hoisting systems with the same hoisting distance and production rate. The mechanical losses depend on the technology used for the two systems, for example the type of bearings and their lubrication system. Also Blair hoists can have two, three or four white metal bearings while a friction hoist of the size required for this example would have two bearings of either white metal or spherical roller bearing type. A reasonable assumption is that the mechanical losses of the drum hoist in... 

The most efficient utihzation of the motor losses is apphcable in locations with smnmer/winter climate where the hoist room needs heating during a substantial part of the yeru. The outlet ur from the motor is directly vented into the hoist room. A controlled damper instcJled in the wall outlet is opened when the ambient temperature is high. Another controlled damper is installed between the hoist room and the motor ventilation intake air plenum chamber. In this way the inlet air is preheated in the cold season. This reduces or eliminates the need for separate preheating equipment which would otherwise be required, which in turn would increase the total energy consumption of the hoisting system. A summary of different heat recovery equipment is shown in Table 10. 

There are a number of triggers that lead to modifications of an existing hoist system that may involve compliance or re-certification to current legislative requirements, and any of the points listed below will Invariably impact on the safety sub-systems, both electrical and mechanical. 

The hoisting system considered is a double drum hoist with a skip/skip configuration. A friction hoist was not considered for this apphcation because of the number of ropes that would have to be handled underground with the similar power requirements did not give a... 

This paper is written from an Australian perspective and primarily in consideration of the requirements of future Australian mining operations. The trend towards mass mines (e.g., block cave, sub-level cave results in the requirement for large capacity hoisting systems from medium depths (1000 m to 2000 m). 

Ore hoist system The option to deepen the shaft was excluded. If the mining operation requires a hoisting capacity from level 1500 or deeper a new blind shaft with a new hoisting system has to be installed. 

Loading station ore storage—provides surge capacity between mine and hoisting system and also required for conversion of continuous ore flow to batch flow for shaft hoisting... 

The hoisting system design and particularly the headframe and collar needed to accommodate requirements for the shaft blind sinking and development phase for the shaft whilst maintaining the shortest possible implementation schedule. The key aspects that needed to be incorporated into the design to cater for shaft sinking included ... 

Hatch Goba (Pty) Ltd (Hatch) has been retained by the Client to design the shaft complex, including the shaft steelwork, shaft loadout conveyors, headgear and hoist house with all the required equipment specified by Hatch. As part of this work Hatch specified, enquired and adjudicated the offers for the hoisting systems for the Deeps Project. 

Using two motors on the Rock Hoist, which are interchangeable with the motor on the Personnel/Material Hoist, provided a motor rating in excess of optimal duty cycle requirements for the Rock hoist. Calculations have been produced to estimate the effect of using overrated versus optimcd size motors on the rock hoisting system power consiunption. 

A Trade-off performed by Hatch indicated that an electrically coupled Blair hoist had a higher initial capital cost (around 10% more initial cost for the complete hoisting system), heavier electrical components, which would impact on the Hoist house crane capacity requirement, and would consume around 30% more power for the same duty through the life of the mine. These aspects made the Hookes joint option more attractive in this rock hoisting application. 

Alternatively, a hoisting system that doesn t require a hoist or ropes, but something akin to magnetic levitation or some self-driven conveyance that has infinite depth potential is a breakthrough that would revolutionize the industry. 

Typical applications for adjustable-voltage, adjustable-speed dc drives include winders, paper machines and auxiliaries, blending systems, feeders, extruders, calendars, machine tools, range and slasher drives, cranes, hoists, shovels and draghnes, and an almost unhmited variety of drives requiring the flexibility and efficiency possible with direct current. 

Fig. 2.56. Freeze drying plant, type CONRAD 800, as shown in Fig. 2.54. In this plant, two trays are pushed in parallel through the tunnel. The two heating systems can be seen, and in front of these are the two lifts, which hoist the tray to required level. The two locks for the trays are on the left and right side, in the lower part of the tunnel. This plant produces approx. 3000 tonnes of freeze dried coffee granulate per year (photograph Atlas Industries A/S, DK-2750 Ballerup).

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