Stockpile configuration

 To run any plant continuously, the basic requirement is the continuous supply of raw material. For example, to run a Thermal power-plant or Steel plant or an Alumina plant, continuous supply of the raw materials viz., coal / iron ore / bauxite / limestone is required.

Unfortunately, it is difficult to guarantee the continuous supply of raw material due to various factors viz., availability of raw material, transporting the raw material (by ship, wagon etc.,) or force majeure.

Hence the solution is to store more than the required amount of these required raw materials in the plant itself.

‘Google’ defines stockpile as, ‘a large accumulated stock of goods or materials, especially one held in reserve for use at a time of shortage or other emergency’.

Why the raw materials to be stacked and not dumped?

It is because of the following limitations,

·       availability of space

·       quantity of material to be stored

·       equipment* used

·       plant process requirement

·       stacking* pattern

·       reclaiming* method

(* - shall be discussed separately in detail)

Configurations of stockpile:

A stock pile shall be conical, circular, triangular or trapezoidal based on the type of machine which is used to stack the material.

·       By using a luffing non-slewing stacker machine, conical and triangular shaped stockpiles shall be formed.

·       By using a luffing cum slewing stacker machine, conical, triangular and trapezoidal stockpiles shall be formed.

·       By using a circular stacker machine, conical or circular stockpiles shall be formed.

A simple yet tricky question:

For the same length of stockpiles, which stockpile gives the maximum storage capacity? A triangular stockpile or a trapezoidal stockpile?

Ans: It depends upon which of the following factors we are concerned with,

1.   the width of the stockpile

2.   the height of the stockpile

For the same width, triangular stockpile gives the maximum capacity and for the same height, trapezoidal stockpile gives the maximum capacity.

Another simple yet tricky question:

In a given area, how to increase the capacity of a stockpile without increasing the width and height of the stockpile?

Ans: By constructing a wall on one side of the stockpile, the capacity of the stockpile shall be increased.

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A follower has asked a question in the previous post. Since the question is relevant to this post, I have copied that question and answer over here for your convenience.

Q: Is there any limitations to maintain the stockpile heights for different materials, like iron ore stockpile, coal stockpile etc.,

A: Since Iron Ore, Bauxite, Alumina, Lime stone, Salt are NON-VOLATILE materials, there is no limitation in stockpile height. This doesn't mean that you can go up-to whatever height you wish since this will have a major impact in the machine configuration and the operating angle of boom and the tripper. Increasing the stockpile height results in increase in the boom pivot point height and the height of the machine. Hence it is advised to go with optimum stockpile height of 10m to 16m.

In case of Coal and Lignite being VOLATILE materials (ie., they can catch fire on their own when stacked – see the below photo), it is not advisable to stack with maximum height. Also, it depends upon the customer requirement since in my experience I have designed Bucket Wheel Stacker Reclaimer machine for 20m height coal stockpile and for 14m height Lignite stockpile (also I would like to highlight one more thing, one of the customers restricted the height of the Lignite stockpile to only 6m).

In general, the height of the stockpile shall be defined by the customer/consultant based on the tests they have done on the material they have planned to stock and also based on their experience. Else you can give your suggestion based on your experience (with the help of supplied machines).

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