by RockRoadRecycle staff writer

Concrete and cement production is generally undertaken at specifically designed stationary processing plants. Here conveying systems are integral components of the set up, being vital to the entire operation of the plant. 

Although the conveying systems used are often very similar, many manufacturers are developing systems to work in highly specialized ways and in a variety of industries. 

Tunnel projects are now often major sources of recycled aggregate and other materials, with the large amounts removed via customized conveying systems being used to form the sub base of connecting roads.

Although there are many specialized material processing plants that are designed to turn waste construction materials into reusable product, the often mobile nature of crushing and screening plants used in processing has led to a relatively recent development — that of tracked conveyors which are able to move and process in tandem with the tracked crushers and screens.

Crushing and screening manufacturers

Conveying systems are in reality pretty similar. The equipment is designed to move material. Conveyors and systems for finer aggregate and sand are more focused on ensuring the material is able to be moved speedily and safely with little or no spillage, while recycling conveyors — especially those dealing with demolition arisings — tend to be heavy duty.

Although often not a primary part of their offering, most screening and crushing systems manufacturers offer ranges of conveying systems as part of their plant designs. These can be configured to exact customer specifications and incorporated into the full material processing solution.

Companies such as McClanahan, Eagle, McCloskey, Superior, Steadman, Terex, Telsmith, Pioneer Kolberg, etc. manufacture and supply conveying equipment.

Although the company divested much of its Mining Systems in 2017, Sandvik Mining and Rock Technology still provides conveying systems as part of its stationary crushing and screening offerings, with the main use being in aggregate plants. 

Sandvik has in recent years worked to develop crushing and screening equipment, which is ideal for manufacturing sand from naturally occurring rock, which is proving to be a significant improvement on the final concrete and cement product.

Multiple use conveyors

German company H+E Logistik has developed a reputation for providing contractors with excavated material removal systems capable of meeting even the most unlikely of requirements. Its conveying systems have been found successfully working underwater, in the centre of a city or high up in the mountains. Wherever they have been put to work, the company’s high-tech systems have ensured that projects are handled on time even under extensive and extreme conditions. 

One interesting development the company is particularly proud of has been that of its booster stations, which have enabled extensive conveying systems to operate even with the tight bends of complex aggregate production facilities. The stations have proven ideal where space is limited, but still require excavated material to be transported without impairing the surrounding infrastructure.  All the company’s conveying systems are available with an extensive range of accessory’s, including touch panel control and surveillance cameras, belt scales, metal detectors, overfill sensors and covering hoods for the upper and lower belt covers.

Keeping the systems working

Making sure conveying belting is maintained in order to move material is equally as important as the belting itself. Canada’s Shaw-Almex has developed conveyor belt vulcanizing presses to hot-splice all types of conveyor belts. Almex heavyweight vulcanizing presses splice fabric ply and steel cord conveyor belts, whereas its lightweight presses are used for PVC, polyurethane and polyester mono filament synthetic belting. 

Both vulcanizer types offer a continually expanding menu of ancillary items including belt splicing tools, belt specific tool kits, conveyor accessories and other splice tools.

In addition to the above, the Almex Group Fusion Systems provide a single global source for a comprehensive line of pulley lagging, cold bond splicing material and repair materials. The Almex fusion lining, impact, wear and corrosion protection products reduce maintenance costs associated with abrasion damage to key components of conveyor belt systems.

Tracked stacking conveyors

A relatively recent trend in conveying systems has been the development of tracked conveying systems. The use of tracked conveyors often means increased stockpile capacity and reduces on-site material handling, while delivering full mobility. Although not able to deliver the same levels of production as stationary plants — nor are they designed to be — they offer other benefits which are now proving to be particularly valuabe to material processing and handling companies world-wide. 

The range of Terex tracked conveyors can be bought from Powerscreen, Terex Finlay, CBI, EvoQuip, Terex Ecotec, Terex Washing Systems or Terex Minerals Processing Systems. Terex Ecotec’s stacking conveyor range currently consists of two self powered tracked options, 65 foot and 80 foot. Transport costs of each conveyor are kept to a minimum, due to the compact transport design, allowing them to be easily tracked in and out of a 40ft container and shipped globally. A simple yet robust design allows for easy setup and positioning, fitting the customers’ requirements. The 36.4.3kW (49hp) Deutz engine and powerful hydraulic drive deliver impressive capacities of up to 400tph.  The design also provides a full range of high specification options, including full under belt and head drum guarding, radio control movement and setup where required.

Terex’s relatively new 100 foot stockpiler builds on the hugely successful 65 foot and 80 foot conveyors. The extra length of conveyor and increased power allows for maximum mobility and flexibility. The conveyor can cope with all applications, from light duty screened material, aggregate for cement and recycled concrete — in fact more or less any material it encounters.  

The company’s tracked radial stockpiling conveyor has proven to be an ideal solution for stockpiling after mobile crushing and screening plants, with the mobility and flexibility of the conveyors reducing or eliminating the use of a wheel loader on site. 

One of the early developers of tracked conveyors was Telestack, whose bulk material handling products are designed to handle all free flowing bulk materials including ores, coal, aggregates, fertilizers, grains, woodchips, pellets, etc. 

All the conveying solutions are designed to reduce the need for haulage on-site and support tracked crushing and screening operations.

Telestack states that it supplies the widest range of tracked stockpiling conveyors with lengths ranging from 50-feet (15m) to 101-feet (31m) able to deliver tonnages ranging from 100tph up to 1500tph and lump sizes up to 12 inches (300mm). The company is also able to supply its conveyors in a “links” system, which aims to reduce or eliminate the need for truck or wheel loader haulage on site. 

The link conveyors can either be track mounted, fully self-driven or wheel mounted / towable wheel mounted.  Also, its mobile and flexible products have been designed to reduce or eliminate degradation, segregation and compaction of material in the cement product process, and to ensure only in-specification material is fed into cement plants.

EDGE Innovate’s range of material handling equipment offers operators an efficient, reliable and robust material handling solution. The EDGE brand name is intrinsically linked to the manufacturing of mobile and track conveyors, feeders and radial track stockpilers, all of which have been designed to improve productivity and mobility while minimizing operator costs. The company states that as a leading manufacturer of conveying solutions, it is acutely aware that one style of conveyor is nowhere near sufficient enough to meet the differing requirements of each material handling operation. 

Differing discharge heights, transfer lengths, condition of terrain, availability of power, the frequency of repositioning and throughput are all factors that must be taken into account when an operator is determining what solution meets all of their requirements. With a “one size does not fit all” mind-set, the EDGE Innovate material handling range of equipment offers a wide variety of stackers and feeders to suit specific material handling requirements including low-level feeder stackers and radial stackers with the option of wheeled or tracked units.

Finnish crushing and screening giant, Metso, has developed its own tracked conveying system. The mobile conveyor adds flexibility to Lokotrack multistage crushing and screening applications and is said to enable easy and fast closed circuit operation even with special combinations. When in open loop, a high discharge height increases the stockpile capacity, and with an additional radial drive (on model CW3.2) the discharge end can be moved radially.

Its Lokotrack® CT3.2™ is powered by the CAT® C2.2 and for the wheel mounted CW3.2, a power pack is available as an option. Additional features include a rock box, impact bars and double drive making the CT3.2 an ideal conveying solution for different feed sizes and capacities. Both systems are easy and safe to use, especially when hydraulic tilting is applied. Spare and wear parts as well as Metso support are available as for any other Lokotrack crushing and screening plant.

Material is typically fed by conveyor into the feed chute and from there is conveyed onward. Discharge height can be adjusted and depending on feed material rock box, impact bars and double drive can be utilized. The conveyors are ready to use within minutes: drive it off the trailer, open tilt tail and discharge end, adjust the angle and start the conveyor. Track drive makes it easy to move on site just like any other Lokotrack unit.

More than just a conveyor

The complexities of modern quarries, recycling plants and cement manufacture means that not only crushing and screening systems have developed, but also the material-moving or conveying systems. They must be tough for recycling applications, precise for moving fine aggregates for sand and have support systems that can repair any problems — and tracked conveyors are now becoming more frequent in quarries, surface mines and construction projects with capabilities to match virtually any requirement.