Think about a coal handling yard where the conveyor is running, the trucks are waiting, and the upcoming batch of coal needs to reach the processing unit. However, to keep the ongoing pace, the material handling equipment struggles. Each late loaded cycle adds to the waiting time. While lifting material spills, this is the reason why the operators should spend extra time cleaning the handling portion.
Each disruption may seem trivial in itself. But when it comes to mines where huge amounts of materials need to be moved every single shift, such problems have a great impact on productivity. This is where a clam shell grab plays an integral role in bulk material handling. These attachments serve to move loose materials, and with them, mining organizations can efficiently move coal, coke, and loose overburden.
Why Is Delay in Coal Mining Material Handling Expensive?
The process of mining does not only include excavating material beneath the earth’s surface. After extracting coal, its transportation, storage, processing, and delivery are necessary. All these procedures will involve effective material handling. The process becomes even more difficult when the facilities have to handle materials with different physical properties.
- Coal: The fine coal and the larger pieces of the coal should be handled properly to avoid spillage while loading and unloading them.
- Coke: Due to its non-uniform particle size and creation of fines, coke needs careful handling.
- Overburden: The loose soil, gravels, and smaller pieces of rocks might require heavy-duty handling machinery.
If the machinery does not work well for such materials, the operators can face a slow loading process, maintenance problems, and interference with the process downstream.
A proper clamshell bucket would help deal with these issues, as the bulk materials could be collected, lifted, and unloaded.
How Does Clam Shell Grab Function in Coal Handling Process?
A clam shell grab comprises two hinged shells that can open and close in relation to loose material handling. After positioning the grab on the material heap, it opens up and then closes to collect the material for lifting by the crane to the discharge point.
Four basic stages can be recognized in the function of the clam shell grab:
- Positioning of the open grab on the material heap.
- Collection of coal, coke, or other loose material within the closed shells.
- Lifting of the loaded grab and moving to the discharge point.
- Opening of shells for unloading into a hopper, truck, or any other storage.
Electro-hydraulic grabs utilize hydraulic power to open and close shells during handling cycles. Unlike conventional mechanical grab which may use ropes and crane movement for shell opening and closing, electro-hydraulic grabs offer powered shell actuation. This makes them a good option for repetitive handling of material.
Proper Handling of Coal, Coke and Overburden by the Proper Grab
It should be noted that not all mining materials are the same. The grab handling effectiveness depends upon its characteristics.
Handling Coal at Stockyards and Loading Stations
The coal handling stations normally handle large amounts of loose coal from stockpiles, loading or unloading areas, and process systems. A clamshell grab can aid in this activity by picking up loads of material in one lift and dumping them to the appropriate place. Aligning the shell shape will assist in holding on to the loose coal when transferring.
Handling Coke in Industries
There are various coke applications in metal manufacturing, especially in the production of iron and steel. In coke handling, too much dropping and uncontrolled discharging will result in high breakage and fines production. A properly designed clamshell bucket makes it possible to control the discharging point of the material. This is important in steel works material handling, where continuous movement of raw materials makes it easier to manufacture.
Handling Loose Overburden in Mining
Overburden may consist of soil, gravel, loose rocks, among others that need to be cleared for mineral deposits. If overburden is loose and appropriately sized, then there may be a need for a heavy-duty grab for specific loading or transferring. Compacted soil, big boulders, and abrasive rock pieces need to be carefully considered when choosing the right equipment. A clamshell grab is not an excavating machine.
How Clam Shell Grabs Aid in Cutting Down on Operational Interruptions?
The use of material handling equipment does not only entail lifting heavier loads. The aim is to ensure smooth operations without interruptions.
Loading and Unloading Operations
An adequately proportioned clam shell grab will enable efficient handling of substantial materials with each grab lift. This minimizes interruptions to the process of loading.
Minimal Material Loss
The effective closing of the shell helps to keep materials within the grab. Minimal material loss will result in less time taken to retrieve materials.
Flexible Crane Mounting
Electro-hydraulic clamshell grabs may be used with various types of crane installations, namely:
- EOT cranes for fixed industrial handling of materials.
- Fixed cranes for designated areas of loading or unloading.
- Mobile cranes for handling operations that require mobility.
The choice of the proper mounting system is vital for equipment installation.
Lower Risk of Unplanned Maintenance
With the right hydraulic operation, component selection, and proper maintenance, unplanned failures are avoided. At the same time, to prevent any downtime, regular inspection of hydraulic cylinders, hoses, seals, pivots, and other components is needed.
Clam Shell Grab and Scrap Handling Grab: Why Equipment Selection Is a Priority?
Sometimes mining and industrial plants have operations where coal, coke, scrap metals, and others are handled from the same operating area. Nevertheless, there are some cases when one type of grab may be inappropriate for use. For instance, a clamshell grab is usually a more appropriate device for bulk materials, like coal, ore, and others.
An orange peel grab is more appropriate for scrap metal handling and other bulky materials. The reason is the multiple tines, which can lift materials that cannot be lifted using two shells closing together. Choosing the equipment according to material specifications prevents inefficiency in loading and possible equipment wear.
Selecting the Right Clam Shell Grab for Mining
Several aspects should be considered before purchasing a grab:
- Material density: This will help determine the load weight carried by the bucket.
- Capacity of the grab: It is advisable to choose an ideal volume for the required handling operation.
- Crane specification: Lifting capabilities, mounting facilities, and power supply should be considered.
- Type of materials: Particle size, abrasiveness, moisture level, and flow properties should all be taken into consideration.
- Access for maintenance: Hydraulic and mechanical systems are easily accessible.
The electro-hydraulic clamshell grab comes in several volumes depending on the handling requirement: 1 to 8 cubic metres for industries. However, the choice should be made considering the grab and material weight.
Final Thoughts
Effective coal handling calls for machinery which ensures consistent flow of material despite challenging operating conditions. A properly selected clam shell grab will enable a facility to load loose coal, coke, and even appropriate overburden without wasting any material during the process.
JEHEL provides electro-hydraulic clamshell grabs from 1 to 8 cubic metres with EOT, stationary, and mobile crane installations. With in-house engineering expertise, customization services, and after sales support, these systems will aid in developing bulk material handling capabilities for any industry facility. Facilities looking forward to enhancing their coal handling capacity should consider proper selection of the grab setup.
