Coal Processing

The preparation of ROM coal commences the moment it is received from the mine. The Rotary Coal Breaker crushes and breaks the coal and removes the majority of the rock contamination.

The sized coal from the Rotary Breaker can then be fed into a Rolling Ring Crusher which produces a finer product.

For more specific and smaller sizing of the coal, the Double Roll Crusher is generally the preferred machine, particularly for processing the sizes required by power stations and for the export market where tight specifications are required.

Serving the South African coal market for more than 80 years, Osborn’s Coal Crushers have proven to be extremely reliable and have gained popularity as far afield as Australia, Turkey and neighbouring African countries, such as Zambia, Zimbabwe, Botswana and Mozambique.

Mineral Sizers

Astec’s range of single shaft and twin shaft roll sizers are rugged by design and engineered to handle high tonnage throughput using minimal installed primary power. The mineral sizers can be configured to operate in two ways depending on the material output size required.

Horizontal Shaft Impact Crushers

Impact crushers may be applied as primary or secondary crushers in applications processing soft, low abrasion materials.

Double Roll Crushers

Equipped with adjustable clearance between the rolls, double roll crushers are typically applied where greater control over product sizing is desired. Larger models are capable of accepting 600 mm (23.6”) feed.

American Roller Ring Crushers

Well suited for most coal crushing applications requiring a top size output from 12 mm to 38 mm (.47” x 1.5”). Larger models are capable of accepting feed particles as large as 600 mm (24”). Available in sizes that range from 30 HP.

Rotary Coal Breakers

Rotary coal breakers are typically utilized for the primary breaking and cleaning of run of mine coal. An assortment of lifters and plows are installed in various arrangements to control flow rates for optimum efficiency.

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Osborn Rotary Coal Breaker

The preparation of ROM coal commences the moment it is received from the mine. The Rotary Coal Breaker crushes and breaks the coal and removes the majority of the rock contamination. The sized coal from the Rotary Breaker can then be fed into a Rolling Ring Crusher which produces a finer product.

For more specific and smaller sizing of the coal, the Double Roll Crusher is generally the preferred machine, particularly for processing the sizes required by power stations and for the export market where tight specifications are required. Serving the South African coal market for more than 80 years, Osborn’s Coal Crushers have proven to be extremely reliable and have gained popularity as far afield as Australia, Turkey and neighbouring African countries, such as Zambia, Zimbabwe, Botswana and Mozambique.

The Rotary Breaker works on a gravity method to break coal in a very efficient manner through attrition. Material is continuously introduced at the feed end, repeatedly raised by the lifters and dropped until it is broken to size and falls through the perforations in the screen plates to a collection hopper below. Any hard rock present in the feed material assists with breaking the coal during the raising and dropping action.

The Osborn Rotary Breaker is designed to reduce soft to medium coal and is not entirely suitable for hard coal or coal with a high moisture content. Mine rock, refuse and other uncrushable debris is automatically carried to the end of the drum and is discharged through a chute.

The Rotary Breaker design incorporates a chain and sprocket drive arrangement which drives a heavy duty reinforced drum. Renewable perforated plates are fitted around the interior of the drum. Interchangeable lifters and ploughs are bolted on the inside of the drum. Due to variations in the types of coal being processed; capacities and power requirements will vary from Mine to Mine.

Osborn Rotary Breakers are capable of processing up to 2 000 tph with a maximum feed size of 600 mm depending on the type of coal being processed. Generally, the machine is fitted with perforated plates to continuously produce one product size. Should the product size need to be changed, new sized perforated plates would have to be fitted.

For more specific and smaller sizing of the coal, the Double Roll Crusher is generally the preferred machine, particularly for processing the sizes required by power stations and for the export market where tight specifications are required.

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Double Roll Crusher

Osborn Double Roll Crushers can be used for primary and secondary crushing. The Double Roll Crusher is generally regarded as a 4:1 feed to product ratio crusher; however in some instances, dependent upon material friability and hardness, it is possible to achieve a 6:1 crushing ratio.

The feed material should enter the centre of the gap between the two rolls and spread across the full roll width for maximum efficiency and this ensures a uniform product size distribution.
For strict coal product specifications the Osborn Double Roll Crusher is preferred. It is important to understand the material characteristics, as the type of coal will often vary considerably. Hardness, rock content, friability and moisture content are the major factors that need to be identified, together with the crusher capacity, maximum lump size, required product size and the amount of fines that are acceptable.

Efficient crushing will lower the power requirements and increase the life of the crusher segments. When the correct crushing ratio is used and the optimum roll diameters selected, the segments will grip the feed material more efficiently and it will also not allow pieces to roll on top of the segments due to the incorrect nip angle, this assists in reducing wear.

Crushing rolls and drive

Each roll assembly comprises of renewable and reversible toothed segments, bolted and keyed to a robust hexagonal hub with the nuts inside the hub. Locking nuts are securely located in fabricated pockets in the drum. This enables removal and replacement of segments from the outside using only one tool (Allan Key).

Bolt heads are protected from excessive wear by being counter sunk in recesses on each segment. Teeth are
arranged in a staggered formation on the segments to prevent tooth on tooth impact. Tooth proportions are designed for the particular product requirements.

The rolls are separately driven by two identical motors, through sets of vee belts which are connected between the gearbox pulley and the flywheels.

The drive arrangement is free standing with the electric motors mounted on adjustable base plates.

FRAME & CANOPY

Fabricated channel beams serve as the main frame support. For ease of adjustment, machined low friction polymer pads are provided. Inspection doors are provided at the roll ends on the non-drive side as well as on the crusher ends. Flanges are provided on the top for connecting a feed chute.

RELEASE MECHANISM

Uncrushable material entering the rolls will load the springs causing them to compress and allow the passing of the non-crushable objects.

Compression springs are fitted at one end and act on the bearing housings of one roll. Spring adjustment bolts and shim plates are fitted for adjusting the roll position. Hydraulic roll adjustment and force relief cylinders can be supplied instead of the springs as an optional extra.

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BTI Rock Breakers

BTI’s BXR Series Breakers offer outstanding power to weight ratio, and exceptional efficiency with the oil regeneration system. Overall system designed for harsh, continuous duty for use in demanding rock breaking applications.

  • Two speed hydraulic pilot power control; controls blow energy in varying material conditions.
  • Oil regeneration system; increases bpm's without decreasing energy in harder material applications.
  • High volume nitrogen charged accumulator; provides constant blow energy and recoil absorption.
  • Extra-long stroke pressure balanced piston in conjunction with oil regeneration system; optimizes impact energy and bpm's.
  • Button nose piston design; maximizes energy transfer to the tool.
  • Anti-blank fire interlock; protects front head and retainer pins.

The design of the BX Series of Hydraulic Breakers produces stable high-speed percussion, and exceptional value and durability for all construction, demolition, and rock breaking requirements.

  • Breaker mounted manual high / low stroke selector (BX8-BX40); improves production capability.
  • Long stroke piston design; provides high levels of constant blow energy.
  • Anti-blank fire on / off selector (BX8-BX40); alternate modes when operating in varying rock conditions.
  • Optimal sound dampening (BX6-BX40) further lowers noise levels, pertinent in high density population areas.
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