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Conveying














A ThorStacker T140 in action at the Ruby Hill Fossicking Reserve Mine, 430km north of Sydney.
A ThorStacker T140 in action at the Ruby Hill Fossicking Reserve Mine, 430km north of Sydney.

The advantages of mobile conveying and loading solutions

The traditional transportation of aggregates from the face to the stockpile has been the trusty sales loader. However, mobile conveyors are providing a viable alternative for the production of cleaner, segregated stockpiles, streamlining of traffic and the reduction of diesel power and emissions.

Why are many quarries today adopting mobile telescopic conveyors instead of relying on haul trucks and wheel loaders?

Well, for starters, the mere act of driving loaders on stockpiles to stack materials as high as possible adds to the problems of compaction and segregation.

Telescopic conveyors help reduce these problems through a unique stockpile creation method that relies less on the need for loaders and trucks. In turn, the mobile conveying solution reduces the risks associated with contamination of materials.

Other incentives to shift towards an automated materials handling system that leverages a telescopic conveyor include higher efficiency, less manual labour, lower training expenses and decreased equipment wear and tear per tonne. What all this adds up to on the bottom line is lower operating costs and increased product quality.

Let’s look at the mechanics of a telescopic conveyor, and how it differs from a regular conveyor.

With the ability to move linearly along the length of the outer conveyor, the inner (or stinger) conveyor shifts the location of the discharge pulley by indexing in and out (see Figure 1). The height of the discharge pulley and the radial position of the conveyor are also variable, allowing the operator to build a layered pile.

Figure 1. The inner conveyor shifts the location of the discharge pulley by indexing in and out.
Figure 1. The inner conveyor shifts the location of the discharge pulley by indexing in and out.

The stockpile creation method eliminates loaders and diminishes risks of contamination of materials.
The stockpile creation method eliminates loaders and diminishes risks of contamination of materials.

It is this three-axis variation of the discharge pulley that allows the telescopic conveyor to overcome segregation and compaction of the material. This is extremely valuable when working with crushed stone material. Unlike a traditional radial stacker, the telescopic stacker has three reciprocating movements:

  1. A radial movement, allowing a 270° circular stockpile creation.

  2. An elevating movement providing stockpile heights exceeding 12m.

  3. A telescopic feature (in/out) on a second integral conveyor permitting a wider base to the “layered” stockpile.

Figure 2 shows a fully extended and elevated telescopic stacker can outline the shape of the stockpile it is capable of producing.

Figure 2. A fully extended, elevated telescopic stacker outlines the shape of the stockpile it can produce.
Figure 2. A fully extended, elevated telescopic stacker outlines the shape of the stockpile it can produce.

Figure 3 depicts a shape, volume and capacity comparison between a conventional conical stockpile and a non-segregated “layered” stockpile “engineered” by telescopic radial stacker technology.

When these telescopic stacker conveyors are configured to work in tandem with transfer conveyors, material can be moved directly from the pit into stockpiles without much manual labour, thereby increasing efficiency and product quality, since there is little contamination imparted onto the material by trucks and loaders.




Figure 3. Calculations based on 1000kg/tonne and 1601.85kg/m3.
Figure 3. Calculations based on 1000kg/tonne and 1601.85kg/m3.

In action

In August 2002 the first ThorStacker telescopic conveyor arrived in Australia, designed for a capacity of 800 tonnes per hour (tph) with the ability to stockpile about 90,000 tonnes of material at a single location when set to a full 270° arc.

Across New South Wales and Queensland today, Thor Global’s mobile telescopic conveyors are still moving coal and aggregate in several mines and quarries.

Three ThorStackers are currently in use in Australia. The ThorStacker is a popular choice in Australian quarries due to its high performance, durability and safety. There are three models of ThorStacker, which differ primarily in their lengths:

  • T140 – 42.7m

  • T150 – 45.7m

  • T190 – 57.9m

Each ThorStacker is equipped with a standard programmable logic control, which allows the telescopic stacker to deposit aggregate in a continuous series of “layered” radial windrows, preventing the gravitational separation of large and small particles.

The load equalising system also comes as standard, and this feature provides the overall machine structure with greater support and longevity under the stresses of heavier loads. The conveyors are also equipped with a fully braced undercarriage, to allow their upper and lower portions to be fully braced at all times.

The machines also have the optional hot-dip galvanising feature, which provides durable, long lasting corrosion protection, even in the harshest of environments.

Coating the machines’ steel in zinc relieves the internal stresses of welded components and gives the machine a very high relative corrosion resistance.

The stacker conveyors are also equipped with a specialty 750mm walkway, added to the outer truss of the conveyor on one side of the machine for increased maintenance accessibility. Platform widths of 610mm and 750mm are available, and all walkways are hot-dip galvanised for maximum durability.

Another specialty feature is the ultra-lightweight belt cover, constructed with galvanised steel structural tubing and single bolt connections, making these conveyor covers easy to handle, remove and assemble. Individual spring tensioning systems keep the covers secure and accessible for maintenance and repair.

Lightweight UV-resistant polyurethane material can reduce the wind load by up to 80 per cent. These belt covers provide excellent dust control, and can be easily installed into any Thor Global conveyor system.

The T190 features an ultra-lightweight belt cover constructed from galvanised steel.
The T190 features an ultra-lightweight belt cover constructed from galvanised steel.

Power options

When using electrical power, the costs associated with fuel usage to operate these telescopic conveyors decreases between 15 and 20 per cent compared to a manually created stockpile. An electrically powered ThorStacker requires no fuel and creates no emissions.

When electrical power is not available on-site, however, fuel can be used, so these machines can operate in remote locations.

A 14kW generator set (or gen-set) can be added to the design of the conveyor, so the machine can still operate on diesel fuel. The T140 is fitted with a gen-set (mounted onto the undercarriage) that allows for increased versatility and mobility.

An aerial view of the T140 at the Ruby Hill Fossicking Reserve Mine.
An aerial view of the T140 at the Ruby Hill Fossicking Reserve Mine.

More than ever, quarries are looking for efficient solutions to the challenges associated with segregation, compaction and contamination, while also ensuring reduced operational costs.

ThorStacker telescopic portable conveyors, with their automated radial stockpiling capabilities, are carefully designed to reduce manual labour, mitigate the need for reprocessing (by reducing compaction and segregation through stockpiling in layered windrows) and reduce the need for loaders and dump trucks (thereby reducing the risk of contamination).

A ThorStacker telescopic conveyor is a viable solution for any quarry looking to meet these challenges.

In Australia, the Lincom Group is the distributor of the ThorStacker and other Thor Global products.

Source: Thor Global/The Lincom Group




















Monday, 20 August, 2018 03:04pm
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