AU2018204171A1 - A method of processing coal - Google Patents

Abstract

A method for use in the mining and processing of coal comprising mining diluted coal at an interface of waste and a coal seam, and processing the diluted coal at a pre treatment plant to produce pre-treated coal and waste. 3661740v1 C'j C0 C~j 't 'J co cm.

Description

A METHOD FOR USE IN THE MINING AND PROCESSING OF COAL

FIELD OF THE INVENTION [0001] The invention relates to a method for use in the mining and processing of coal. In particular, the invention relates, but is not limited, to a method of mining diluted coal and processing diluted coal using a pretreatment plant.

BACKGROUND TO THE INVENTION [0002] Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.

[0003] In the mining industry, coal mined from the top and bottom of a coal seam is typically quite diluted. That is, due to complex geological factors, such as faulting, dipping and rolling of coal seams, and different mining conditions, such as wet weather and night time which affect the ability to avoid diluted coal, the coal is riddled with impurities and waste material that reduces the economic value of the coal. These impurities, which generally include water, rocks and soil, are processed by a typical coal handling and preparing plant (CHPP). In contractual arrangements, significant financial bonuses or penalties may be based on coal recovery and the dilution levels achieved, as measured at the point of entry to the CHPP. At this point the Run-Of-Mine (ROM) stockpile is reconciled against the approved geological model for the mine.

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-22018204171 12 Jun 2018 [0004] In many situations a compromise by the coal miners is made. Either the impure coal is discarded, wasting time, money and resources, or the impure coal is mined and processed which causes severe wear and tear on the CHPP requiring more frequent and expensive maintenance. Another option is to carefully mine the seam in an attempt to avoid as much of the diluted coal as possible and only extract the coal with minimal dilution. This is undesirable as valuable mineral is left behind and significant time is wasted finding the least diluted coal and avoiding the diluted coal. Thus, none of the presently available solutions are ideal.

[0005] To this end, removing some of the waste material, in a pretreatment process, before the run of mine coal is fed into the CHPP, is advantageous. Pre-treating coal, and delivering a less diluted product to the CHPP, reduces wear and tear on the components in the CHPP thus reducing its maintenance costs. Knowing that the coal will be pre-treated allows increased efficiencies when extracting coal from the top, bottom and sides of the seam (the interface) because there is less of an imperative to reduce impurities through the digging process itself. The interface between the waste and the coal seam can be stripped more quickly, and with larger equipment, knowing that diluted coal obtained will be pre-treated before being delivered to the CHPP, thus reducing contractual penalties that would otherwise be imposed. Ideally:

a. more coal is recovered;

b. the mining and coal recovery at the interface is more efficient;

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c. maintenance costs at the CHPP are reduced;

d. there are less tailings to be disposed of after processed coal and waste emerges from the CHPP; and

e. the entire process is more profitable for the participants.

[0006] It is hoped that this invention may provide a method for use in the mining and processing of coal which overcomes or ameliorates one or more of the disadvantages or problems described above, or which at least provides a useful alternative.

SUMMARY OF THE INVENTION [0007] In one form, although not necessarily the only or broadest form, the invention resides in a method for use in the mining and processing of coal, comprising:

a. mining diluted coal at an interface of waste and a coal seam; and

b. processing the diluted coal at a pre-treatment plant to produce pretreated coal and waste.

[0008] Preferably, the method comprises the step of mining minimally diluted coal from within the coal seam.

[0009] Preferably, the method comprises the step of sorting the minimally diluted coal and the diluted coal into separate stockpiles.

[0010] Preferably, the processing of the diluted coal at the pre-treatment plant comprises a beneficiation process.

[0011] Preferably, the processing of the diluted coal at the pre-treatment plant comprises separating the diluted coal into pre-treated coal and waste, optionally using a jig.

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-42018204171 12 Jun 2018 [0012] Preferably, the pre-treatment plant is located in a mining pit. Alternatively, the pre-treatment plant is located remotely from a mining pit.

[0013] Preferably, the processing of the diluted coal at the pre-treatment plant comprises at least one of a screening process, a gravity separation process, and a dewatering process. More preferably, the dewatering process comprises a hydrocyclone and a screw process.

[0014] Preferably, the method comprises the step of transferring the diluted coal to the pre-treatment plant. More preferably, the method comprises the step of transferring diluted coal from a diluted coal Run-of-Mine (ROM) stockpile to the pre-treatment plant. Even more preferably, the method comprises the step of transferring the diluted coal from a diluted coal ROM stockpile to the pre-treatment plant using a front-end loader to load the diluted coal into a hopper at the pre-treatment plant.

[0015] Preferably, the method comprises the step of transferring the pretreated coal that emerges from the pre-treatment plant to a second ROM stockpile comprising the minimally diluted coal.

[0016] Preferably, the method comprises the step of reconciling the pretreated coal and the minimally diluted coal.

[0017] Preferably, the method comprises the step of transferring the waste to a dump site. More preferably, the method comprises the step of transferring the waste to the dump site on a conveyor. Alternatively, the method comprises the step of transferring the waste to the dump site in a truck.

[0018] Preferably, the method comprises the step of transferring the pretreated coal, and the minimally diluted coal to a CHPP. More preferably, the

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- 5 method comprises the step of transferring the pre-treated coal to a CHPP on a conveyor.

[0019] Preferably, the method comprises the step of processing the pretreated coal and the minimally diluted coal at a CHPP.

[0020] Further features and advantages of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS [0021] By way of example only, preferred embodiments of the invention will be described more fully hereinafter with reference to the accompanying figures, wherein:

[0022] FIG. 1 illustrates a flow diagram of a method of processing coal according to an embodiment of the present invention; and [0023] FIG. 2 illustrates a schematic diagram of a system of processing coal according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS [0024] Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.

[0025] Illustrated in FIG. 1 is a method 100 that would be implemented by a miner or group of miners to produce processed coal. In a first step 110 of

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-62018204171 12 Jun 2018 the method 100, a miner mines a coal seam for minimally diluted coal and diluted coal without regard to the amount of either type of coal. The minimally diluted coal and the clean coal are separated into respective ROM stockpiles. [0026] In the second step 120, the diluted coal is transferred to a beneficiation plant for pre-treatment.

[0027] At the next step 130, the beneficiation plant pre-treats the diluted coal using a first process which produces pre-treated coal and waste.

[0028] One example of a process, known as beneficiation, reduces the negative impact of the diluted coal. Beneficiation includes a process that improves (benefits) the economic value of the material by removing undesirable materials therefrom. By way of example, de-stoning coal (i.e. removing excess dilution) improves the quality and value of the coal. Other examples include separation of coal from waste material by screening, and gravity separation process [0029] At a fourth step 140, the pre-treated coal is transferred to a ROM stockpile which includes the minimally diluted coal, and the waste is transferred to a dump site.

[0030] Following step 140, at step 150, the pre-treated coal and minimally diluted coal from the ROM stockpile is reconciled. Reconciliation of coal is a process which typically includes analysing and weighing the pre-treated and minimally diluted coal using a weightometer to determine how much coal has been mined from a seam relative to the gross amount of material removed from a seam. This is important for measuring efficiency with regard to mining as well as measuring delivery of coal material with regard to targets.

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-7 [0031] At a final step 160, the CHPP processes the coal using a second process.

[0032] FIG. 2 illustrates a system 200 for the processing of diluted, or dirty, coal. The system 200 includes a diluted coal stockpile 210, a loading ramp 220, a pre-treatment plant in the form of a beneficiation plant 230, a waste conveyor 240 and a pre-treated coal conveyor 250.

[0033] In operation, the coal is delivered to a truck or front-end loader (not shown) from the diluted coal stockpile 210. The front-end loader then transports the diluted coal up the loading ramp 220 and into a feed hopper of the beneficiation plant 230.

[0034] Once the diluted coal reaches the pre-treatment plant 230, the diluted coal undergoes a first process which separates the diluted coal into pre-treated coal and waste, consisting of rocks and other impurities. The first process can be conducted using a variety of known processes, including using a jig, a screening process or a gravity separation process.

[0035] The separated products are then handled in two ways. The waste product is transferred to a waste conveyor 240 which transports the waste to a dump stockpile or truck for further transport to a remote dump site. As shown, the waste conveyor 240 includes wheels 242 to allow the conveyor 240 to be moved.

[0036] The pre-treated coal is transferred to a coal conveyor 250 which transports the pre-treated coal to a ROM stockpile (not shown). As illustrated, the pre-treated coal is carried at an upwardly inclined angle by the coal conveyor 250 which includes wheels 252 allowing the conveyor 250 to be moved, if necessary.

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- 8 [0037] While the conveyors 240, 250 are shown to be inclined, a person skilled in the art will appreciate that the conveyors 240, 250 can be configured in a number of different ways.

[0038] The coal ROM stockpile can comprise the pre-treated coal alone or may be made up of both the minimally diluted coal and the pre-treated coal.

[0039] Once the pre-treatment plant completes the process, the pretreated coal is ready for reconciliation.

[0040] After the pre-treatment and reconciliation processes have been completed, the pre-treated coal and minimally diluted coal from the ROM stockpile can be transported to a CHPP.

[0041] The CHPP is a facility that performs a further process to further refine the coal, such as washing coal of soil and rock, crushing the coal into graded sized chunks (sorting), stockpile the different grades in preparation for transport to market and loading coal into transport equipment.

[0042] Advantageously, by using this pre-treatment process a coal seam can be mined without regard for the amount of dilution present in the mined coal.

[0043] Advantageously, a greater amount of waste material can be removed from the diluted coal, lowering transport costs and increasing its market value.

[0044] In a further advantage, minimising the amount of dilution present in the coal reduces the penalties imposed on a mining company. Minimising the amount of dilution also reduces the wear on the CHPP.

[0045] Even further advantageously, a higher amount of usable coal can be recovered from a coal seam.

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-92018204171 12 Jun 2018 [0046] In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step, etc.

[0047] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.

[0048] In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

Claims (16)

1. A method for use in the mining and processing of coal, comprising:

a. mining diluted coal at an interface of waste and a coal seam; and

b. processing the diluted coal at a pre-treatment plant to produce pre-treated coal and waste.

2. The method of claim 1, wherein the method further comprises mining minimally diluted coal from within the coal seam.

3. The method of claim 2, wherein the method further comprises sorting the minimally diluted coal and the diluted coal into separate stockpiles.

4. The method of any one of the preceding claims, wherein the processing of the diluted coal at the pre-treatment plant comprises a beneficiation process.

5. The method of any one of the preceding claims, wherein the processing of the diluted coal at the pre-treatment plant comprises separating the diluted coal into pretreated coal and waste, optionally using a jig.

6. The method of any one of the preceding claims, wherein the pre-treatment plant is located in a mining pit.

7. The method of any one of claims 1-5, wherein the pre-treatment plant is located remotely from a mining pit.

8. The method of any one of the preceding claims, wherein the processing of the diluted coal at the pre-treatment plant comprises at least one of a screening process, a gravity separation process, and a dewatering process.

9. The method of claim 8, wherein the processing of the diluted coal at the pretreatment plant includes the dewatering process, which comprises a hydrocyclone and a screw process.

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10. The method of any one of the preceding claims, wherein the method comprises transferring the diluted coal from a diluted coal Run-of-Mine (ROM) stockpile to the pre-treatment plant using a front-end loader to load the diluted coal into a hopper at the pre-treatment plant.

11. The method of claim 10, wherein the method comprises transferring the pretreated coal that emerges from the pre-treatment plant to a second ROM stockpile comprising the minimally diluted coal.

12. The method of any one of claims 2-11, wherein the method comprises reconciling the pretreated coal and the minimally diluted coal.

13. The method of any one of the preceding claims, wherein the method comprises transferring the waste to a dump site on a conveyor.

14. The method of any one of claims 1-12, wherein the method comprises transferring the waste to a dump site in a truck.

15. The method of any one of claims 2-14, wherein the method comprises the step of transferring the pre-treated coal and the minimally diluted coal to a coal handling and preparing plant (CHPP).

16. The method of claim 15, wherein the method comprises processing the pretreated coal and the minimally diluted coal at the CHPP.