Patent Application
20150122705
The present invention relates to a method and apparatus for sorting mined material. Embodiments of the invention find particular, but not exclusive, use in the upgrading of mined material, such as copper, nickel and iron ores.
The following description of the background art refers specifically to copper ores and the extraction of copper metal from copper ore. It will be understood that the description of copper ore sorting, extraction technologies and prices are provided to better contextualise the broader inventive concept described herein, but are not intended to be limiting on the broader inventive concept.
Moreover, any references to specific technologies, methodologies, apparatuses, devices, etc. are not admissions that the technologies, methodologies, apparatuses, devices, etc. form part of the common general knowledge.
While the amount of copper available on Earth is vast, only a small fraction of the copper present on Earth can be extracted from copper ores in an economically viable manner. The economic viability of copper recovery is driven by a complex combination of factors, including but not limited to the market price of copper and the efficiency and cost of mining, upgrading and recovery technologies.
In the year 2011, taking into account 2011 copper prices and 2011 technology, copper ore that contains less than approximately 0.6% copper cannot be mined, upgraded, recovered and sold at a profit using the conventional methods of grinding and flotation. This contrasts with copper ores that were mined in the 1980s, when the commercial cut-off was an ore that contained approximately 5-6% copper.
In other words, over time, the quality of the copper ores being mined has decreased dramatically. With the average concentration of copper being so low in ores currently being mined, the amount of resources (time, effort and financial input) required to upgrade the copper ore and recover the copper metal is ever increasing.
As such, the upgrading of copper ore and the recovery of copper metal from upgraded ore is becoming a more cost and resource intensive process and there is a need to find better processing methodologies that more efficiently upgrade copper ore and consequently more efficiently recover copper metal from the ore.
It is in the abovementioned context that the invention described and defined herein was developed.
In a first aspect, there is provided a method of sorting a parcel of ore comprising the steps of first sorting the parcel of ore into one of at least two grades based on a characteristic of the parcel of ore, and a second sorting step wherein the parcel of ore is further sorted.
The second sorting step may comprise the intermediate step of dividing the parcel into at least two sub-parcels of ore and sorting at least one of the at least two sub-parcels. In this embodiment, the second sorting step includes the step of classifying the parcel of ore or at least one of the at least two sub-parcels of ore into one of a plurality of grades. Moreover, the second sorting step may further comprise the step of providing at least one of the at least two sub-parcels to the first sorting step.
In one embodiment, the intermediate step of dividing the parcel into at least two sub-parcels includes the step of determining at least one of the type of ore and the mineralogy of the ore, and dividing the parcel on the basis of the determination.
Moreover, the step of determining the at least one type of ore and the mineralogy of the ore may comprise the further step of utilising an algorithm to determine at least one of the type of ore and the mineralogy of the ore.
The algorithm may utilise a predetermined database of values as an input to determine the required sub-division of the parcel. The algorithm may further utilise at least one of the size of the parcel of particles and a speed at which the parcel of particles is progressing along a conveyor belt as inputs to determine the required sub-division of the parcel.
In one embodiment, the second sorting step comprises the step of re-sorting at least one of the at least two sub-parcels utilising the first sorting step.
In one embodiment, the plurality of grades includes a barren grade, an intermediate grade and a high grade. In the context of copper ores low grade collection includes copper ore with a copper concentration of about or below 0.3% by weight. A high grade collection includes copper ore with a copper concentration of about or above 0.6% by weight. An intermediate grade collection includes copper ore with a copper concentration of between approximately 0.3% to 0.6% by weight.
Where the ore is of a high grade, the sorting step includes the further step of sending the ore to a recovery stage.
Where the ore is of a barren grade, the sorting step includes the further step of sending the ore to a tailings storage area.
The first sorting step may include exposing the at least one parcel of ore to an electromagnetic field and measuring the resultant emitted electromagnetic radiation from the parcel of ore, wherein the resultant electromagnetic radiation is indicative of a characteristic of the parcel of ore. The second sorting step may include at least one of utilising a magnetic resonance technique, a microwave technique and a radio frequency technique.
The characteristic of the ore may be at least one of the type of ore and the relative concentration of a metal in the ore.
In one embodiment, the ore is a copper containing ore.
In one embodiment, the size of the parcel of ore or the at least two sub-parcels of ore are dependent on at least one characteristic. The at least one characteristic is a function of the average grade of a plurality of parcels of ore.
In a second aspect, the present invention provides an apparatus for sorting a parcel of ore comprising a first sorting device arranged to sort a parcel of ore into one of at least two grades based on a characteristic of the parcel of ore, and a second sorting device wherein the parcel of ore is further sorted.
The apparatus may further comprise a parcel definition device arranged to divide the parcel into at least two sub-parcels of ore, wherein the second sorting device sorts at least one of the at least two sub-parcels. The second sorting device may classify at least one of the at least two sub-parcels of ore into one of a plurality of grades.
The parcel definition device may be in communication with at least one sensor arranged to determine at least one of the type of ore and the mineralogy of the ore, wherein the parcel is divides on the basis of the determination. The parcel definition device may further be in communication with at least one processor that utilises an algorithm to determine at least one of the type of ore and the mineralogy of the ore.
In one embodiment, the parcel definition device is in communication with at least one database which is accessible via the at least one processor, the database including a predetermined database of values utilised by the processor as an input to determine the required sub-division of the parcel.
In one embodiment, the parcel definition device is in communication with at least one additional sensor arranged to provide data to the processor, the at least one additional sensor providing data indicative of at least one of the size of the parcel of particles and a speed at which the parcel of particles is progressing along a conveyor belt, wherein the data is utilised as an input by the processor to determine the required sub-division of the parcel.
The second sorting device may be arranged to feed back at least one of the at least two sub-parcels to the first sorting device.
The first sorting device may include a magnetic resonance system arranged to expose the at least one parcel to an electromagnetic field and measure the resultant emitted electromagnetic radiation from the parcel of ore, wherein the resultant electromagnetic radiation is indicative of a characteristic of the parcel of ore.
The second sorting device may be one of a magnetic resonance sorting device, a microwave sorting device and a radio frequency sorting device.
The apparatus may further comprise a parcel definition device arranged to alter the number of particles in the parcel of ore dependent on at least one parameter. The at least one parameter is a function of the average grade value over a predetermined period of time.
In a third aspect, there is provided a mining circuit including an apparatus in accordance with the second aspect of the invention.
In a fourth aspect, there is provided a mine including an apparatus in accordance with the second aspect of the invention.
In a fifth aspect, the present invention provides a method of sorting copper ore comprising the steps of exposing a plurality of particles of copper ore to a magnetic field and measuring the resultant emitted electromagnetic radiation to determine at least one of the type of copper ore or the relative concentration of copper in the copper ore of the plurality of particles, and sorting the plurality of particles of copper ore on the basis of the determination.
In one embodiment, the method includes the further step of classifying the plurality of particles into one of a plurality of grades. Moreover, the sorting step may include the further step of performing an additional sorting step if the plurality of particles of copper ore is of an intermediate grade.
In one embodiment, the additional sorting step comprises iterating the method steps of the fifth aspect of the invention utilising the plurality of particles of copper ore of an intermediate grade.
In a sixth aspect, the present invention provides a copper ore sorting apparatus comprising a magnetic field generator arranged to expose a plurality of particles of copper ore to an electromagnetic field, a detector arranged to measure the resultant emitted electromagnetic radiation from the particles, and a processing device arranged to receive the measurement from the detector and determine at least one of the type of copper ore or the relative concentration of copper.
Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:
In the ensuing description, the embodiment described refers specifically to the upgrading of copper ore. It will be understood that the methodology and apparatus described herein may be applied to the upgrading of other ores, such as nickel or iron.
Referring to
It will be understood that like numerals in
Referring in more detail to
The type of sorter shown at 100 is generally referred to in the art as a “bulk sorter”, as it is arranged to sort large amounts of ore and preferably in a continuous manner. The sorter 100 includes a conveyor belt 102 (or any other suitable ore transport device) arranged to convey particles of copper ore (generally denoted by numeral 104).
In the context of the present specification, the term “particle” may be understood to be synonymous with the term “fragment”, which is a term used by some persons skilled in the art. In the context of the present specification, a particle may be considered to be a piece of ore that has a diameter of approximately 15-25 mm (although some particles may be much larger). Accordingly, each particles may weigh anywhere from under 10 grams to several kilograms. However, in many commercial mining operations, mined material is crushed into particles that are generally between 5 and 200 grams in weight.
However, it will also be understood that the invention described herein can find application in the sorting of ‘fine’ particles (i.e. particles under 5 grams).
Correspondingly, the number of particles of copper ore 104 that can pass along conveyor belt 102 is a function of the capacity of the conveyor belt 102. Where the sorter 100 forms part of a mined material upgrade circuit, the number of particles of copper ore 104 that can pass along the conveyor belt may also be measured as a function of the capacity and characteristics of other components in the mined material upgrade circuit (examples of which are described in more detail later with reference to
The bulk sorter is arranged to sort a plurality of particles simultaneously. For the sake of clarity, the present specification refers to a plurality of particles as a “parcel of particles”. It will be understood that in the context of the present specification, the number of particles that constitute a parcel is a function of a number of variables, which can change depending on the specific implementation and mining circuit, and also with the type of ore. For example, copper ore generally has smaller particle sizes than iron ore. Moreover, different ores that contain the same metal may also have different parcel sizes. In the example of copper ores, monzonite ores and quartzite ores have different parcel sizes.
In more detail, the number of particles in a parcel may vary depending on a number of parameters, including the size of the particles, the capacity of each upgrading and recovery stage, the total amount of copper ore to be upgraded, or any other appropriate metric. The choice of appropriate metrics may take into account both technical and economic considerations. However, it will be understood that, generally, a parcel contains at least three (3) or more particles and preferably more than ten (10) particles.
Moreover, the size of a parcel may be defined by weight or by defining a parcel as being the plurality of particles that locate along an arbitrary section/length of the conveyor belt 102.
Where the number of particles in a parcel is defined by weight, the total weight for a parcel may be anywhere from approximately 1 kg to approximately 1 metric ton. Where the parcel size is defined as all the particles within an arbitrary length of the conveyor, the parcel size may vary from 0.1 m to 2 m. Obviously, this measurement is highly dependent on the density of particles on the conveyor and the width of the conveyor. A parcel may also be defined as the number of particles that pass a particular point on the conveyor over a given period of time.
In summary, irrespective of the metrics utilized to determine a parcel size, it will be understood that a parcel may be broadly defined as a plurality of particles. In turn, the actual number of particles that constitute a parcel depends on the specific parameters of the mining circuit and in turn, the specific parameters may be characterized by reference to individual or average particle size or weight, the characteristics of the conveyor belt, the characteristics of any other component in the mining circuit, or any combination thereof.
Referring to
The conveyor belt 102 is arranged, in the embodiments shown in
In the context of the present specification, the term “magnetic resonance” refers to a physical phenomenon in which magnetic nuclei in atoms that constitute a material absorb and re-emit electromagnetic radiation in response to being placed in an electro magnetic field. By studying the peaks of the nuclear magnetic resonance spectra produced by the re-emission of electromagnetic radiation from atoms in a material, information can be discerned about the atomic structure and composition of the material.
Correspondingly, the term “magnetic resonance device” refers to a device that is capable of both emitting an appropriate electromagnetic field that is absorbed by a material to be studied and measuring the resultant re-emitted electromagnetic radiation to produce an output signal that can be interpreted by a person or a computing system. The output from the magnetic resonance device may directly or indirectly provide information about the composition of the material and the output may be used to determine one or more components (whether they be atoms, compounds or more complex atomic structures) that make up the material.
In the context of the example embodiments described herein, it will also be understood that references to a “magnetic resonance device” encompass a device that is capable of operating in a mined material upgrading context. That is, the componentry, location and ‘tuning’ of the device is such that it can operate effectively in a mined material upgrading circuit.
The magnetic resonance device 106 is capable of taking continuous readings ‘on the fly’ of successive parcels of particles as each parcel passes along the conveyor belt 102. Upon taking a reading of a parcel, the device 106 sends a data signal indicative of the received electromagnetic radiation to a data processing device 108 (in the form of a computing device), which is arranged to receive the signal and process the signal to provide an indication of the quality/quantity of copper ore present in the parcel of particles and also provide information on the type of copper ore that is predominantly present in the parcel of particles.
That is, the magnetic resonance device is connected via an appropriate network or link to a computing device arranged to interpret the output of the magnetic resonance device and consequently direct a conveyor/sorter (or other appropriate device) to divert particles or parcels of particles appropriately.
It will be understood that while
By identifying the amount and type of copper ore present (e.g. chalcopyrite, bornite, chalcocite or covellite) in the parcel of particles, a decision may be made about the grade of the ore in the parcel or more particularly, whether the ore is suitable for recovery without further upgrading.
In the context of the present specification, a copper ore which contains over 0.6% copper is considered a high quality ore that is commercially viable to recover copper from. A copper ore which contains less than 0.3% copper is considered barren and is not (as at the priority date of this application) considered economically viable to recover copper from. Copper ores that contain between 0.3 to 0.6% copper ore are considered intermediate ores, which may in certain circumstances benefit from secondary analysis (either in bulk or by fragment) to determine whether such secondary analysed parcels or fragments are economically viable to recover copper from, or whether they should be considered barren.
In the embodiments shown in
In yet another embodiment, the output may be utilised to calculate a ‘mean’ or average value for the copper content of a plurality of parcels over a predetermined time.
In more detail, where parcel size is small (less than 100 particles) or where the grade of the parcel is extremely close to the desired cut-off point, losses can occur due an incorrect classification of a parcel as ‘barren’ when in fact the parcel contains a copper content that is above the cut-off point.
One way to ameliorate this problem is to take an average or ‘mean’ reading of a plurality of parcels as they pass through the sorter, to estimate the ‘mean’ grade of the material passing through the sorter and thereby sort individual parcels not on a reading of the copper content of each parcel per se, but on a mean reading across a plurality of similar parcels.
In other words, an analytical tool such as a cumulative sum chart can be utilised to determine when a change in mean grade was developing (i.e. from barren to floatation or vice versa). The operation of the sorter can then be controlled by the above described decision-making strategy. It will be understood that the strategy can be tuned on the basis of the actual variability in mean grade experienced in practice in a particular site.
While not shown in
It will also be understood that while the magnetic resonance device described herein includes multiple components, the device should not be limited to encompass only an apparatus or system that includes multiple components, but should also be construed to include a device or scanner that is a unitary or “one-piece” device, where all components, such as but not limited to the data processing component, are provided in a unitary device with the magnetic resonance device.
Referring now to
Referring to
Barren parcels 208, which are not economically viable to upgrade, are sent to a tailings pond/storage area 220.
Flotation grade parcels 212, which are economically viable to recover copper metal from, are sent to a mill stage 216 and subsequently to a flotation treatment stage 218, each one of stages 216 and 218 being designed to recover the copper metal from the ore.
Intermediate grade parcels 210 are sent to a second parcel sorter 214a. Prior to being sent to second parcel sorter 214a, the parcel may be sub-divided into two or more smaller parcels by a parcel definition device 211. Different blocks in a mine have different mineralogy type ores so the parcel definition device is utilised to optimize the parcel size, so that, in turn, the bulk sorter is always applying the optimum parcel size.
In more detail, the parcel definition device includes an appropriate sensor (such as but not limited to a magnetic resonance device described with reference to
While not explicitly shown in
Depending on the type of ore or the indicative mineralogy of the ore, the parcel definition device 211 compares the type of ore or the indicative mineralogy of the ore to data that exists in the database.
Ore that is predominantly of one type is separated into a different parcel size by the parcel definition device 211 than an ore with another type of mineralogy. In other words, the parcel definition device 211 dynamically changes the parcel size depending on the sensor input and the database of parcel sizes optimized for the specific sensor input.
Other inputs to the parcel definition device 211 may include the speed of the belt, or the size of the ores. For example, the parcel definition device may include or may be in communication with an optical or infra-red camera which uses image recognition software to estimate the average size of the parcels and/or particles on the belt. This information may be used in conjunction with the type of ore or the mineralogy of the ore to dynamically vary the parcel size to correspond with an optimum parcel size for bulk sorting.
Returning to the circuit of
For example, if the original parcel size passed through the sorting device 206 was 500 kg, the smaller parcel size to be passed through the second particle sorter may be 250 kg, or 100 kg, or 50 kg, etc. It will be understood that any suitable fraction may be chosen, depending on the parameters of the mining circuit, knowledge about the ore, etc. For example, where a much higher resolution is desired for the second parcel sorting stage, the smaller parcel may be 5% of the original parcel size. That is, for an original parcel size of 500 kg, a smaller parcel size of 25 kg may be provided to the sorter 214a.
Referring now to
An example of a radio frequency technology that may be utilized to individually probe each particle is described in pending PCT application PCT/AU2010/001712, entitled “Sorting Mined Material”, which is incorporated herein by reference. An example of a microwave technology that may be utilized to individually probe each particle is described in pending PCT application PCT/AU2006/001561, entitled “Method of Determining the Presence of a Mineral within a Material” which is also incorporated herein by reference.
Referring now to
Referring now to
It will be understood that the second run through the sorter 206 may occur immediately (i.e. intermediate grade parcels may be divided and re-introduced immediately) or alternatively, the intermediate grade parcels may be collected and stockpiled, to be passed through the sorter 206 at a later time.
Alternatively, instead of or in addition to dividing the intermediate grade parcels, the intermediate grade parcels may be mixed with mined material that is yet to be sorted before being run through the sorter 206. The action of mixing the parcels to form new parcels may, in certain situations, ameliorate the need to vary the size of the parcels, as the act of mixing may change the overall composition of the parcel and result in new parcels that contain over 0.6% copper or below 0.3% copper.
Such variations in the manner in which intermediate grade parcels are reintroduced into the sorter 206 are within the purview of a person skilled in the art.
The provision of a device in accordance with
Firstly, the most energy, time and cost intensive stages of any copper ore upgrading circuit are the recovery stages, whether they are dry or wet stages, as opposed to the sorting/upgrading stages.
In the example circuits of
Secondly, in addition to better determining the quality of ore in a parcel of particles, the apparatus of
For example, sulfide ores tend to be recovered using a floatation technique (such as the flotation treatment stage 218), since sulfide ores that are naturally high in native copper are generally more resistant to treatment with wet chemical techniques such as sulfuric acid leaching.
In contrast, some sulfide ores can be leached using a bacterial oxidation process to oxidise the sulfides and thereby allow for simultaneous leaching with sulfuric acid to a copper sulfate solution, which in turn can be recovered using a solvent extraction technique.
In other words, more efficient (i.e. cost effective) recovery is achieved where detailed knowledge regarding the composition of the copper ore can be determined ‘on the fly’. This allows mined material to be upgraded and the metal recovered efficiently, with little regard to any changes in the composition of the ore as new parcels of ore are passed through the circuit. In turn, this allows a copper ore upgrading circuit in accordance with the embodiments described herein to accept any prima facie suitable copper ore for upgrading and recovery, without the need to spend an appreciable amount of time ‘tuning’ the circuit to suit a particular ore.
A circuit in accordance with the embodiment described herein also reduces or largely ameliorates the need to “pre-test” mined copper ore prior to providing the ore to the circuit.
By providing a device in accordance with
It will be understood that while the description of an embodiment of the invention focuses on the upgrading of copper ores with particular reference to copper sulfide minerals, the broader invention is not limited to the upgrading of copper sulfide minerals. Indeed, the methods and apparatuses described herein may be used to upgrade other copper phases, such as copper-arsenic phases including enargite and ten nantite/tetrahedrite.
It will also be understood that while the embodiment described herein refers to the sorting and upgrading of copper ores and the recovery of copper metal, the broader inventive concept may find use in the sorting and upgrading of any type of material that contains copper, including man made materials. That is, the invention may find use in recovering copper from alloys or other man-made compositions, which may be ‘scrap’ from building waste, scrapped appliances, or other man-made sources.
It will also be understood that the particular upgrading circuit described herein refers to one implementation of a mined material upgrade circuit that includes a magnetic resonance device, but that the broader inventive concept described herein should not be limited only to the circuits described herein.
That is, the bulk sorter described in the present application is a magnetic resonance sorter, but in the context of the broader invention the bulk sorter may use any suitable analytical technique to determine the basis for sorting parcels of material being processed in the bulk sorting steps. In particular the bulk sorter technology may be based on the radio frequency and/or microwave technologies described for the fragment sorters of the two PCT applications referred to in paragraph 55 above.
Other analytical techniques for the bulk sorting step may include, by way of example, x-ray fluorescence, radiometric, electromagnetic, optical, and photometric techniques.
The applicability of any one or more of these (and other) techniques will depend on factors relating to a particular mine ore or a section of the mine to be mined.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011905039 | Dec 2011 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2012/001469 | 11/30/2012 | WO | 00 |
