[0001] The present invention relates to a measurement device for a core drilling tool.

BACKGROUND ART

[0002] Core drilling tools are commonly provided with measurement devices to obtain data about the geometries of the geology, the nature and properties of the rock surrounding the borehole, the conditions of the borehole, the operation of the core drilling tool and drilling progress, the orientation and properties of the core sample, core recovery parameters, and the like. Such measurement devices may typically be found in association with the inner tube such that they remain in a fixed relation with the inner tube while coring.

[0003] Commercially available measurement devices include assemblies comprising a measurement device which is designed to replace the entire backend assembly of an inner tube. However, such devices are heavy to handle and transport, are often expensive and do not enable a user to replace parts with off-the- shelf components. Other commercially available solutions include a measurement device which can be incorporated into the inner tube assembly. However, this causes an increase in length of the inner tube and requires the addition of an extension of corresponding length to the outer tube to compensate. Unfortunately, such solutions add weight and length to the core drilling tool and create a weak link in the core drilling tool increasing the chances of mechanical failure.

[0004] Thus, there would be an advantage if it were possible to provide a measurement device for a core drilling tool which is easy to assemble, handle and transport, forms part of the standard drilling assembly and is also relatively inexpensive.

[0005] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country. SUMMARY OF INVENTION

[0006] The present invention is directed to a measurement device, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0007] With the foregoing in view, the present invention in a first aspect, resides broadly in a measurement device for a core drilling tool, the device comprising: one or more data acquisition portions, and a housing portion configured to receive and retain the one or more data acquisition portions, wherein the measurement device is adapted for removable connection to a backend assembly of the core drilling tool.

[0008] The measurement device may be used with any suitable core drilling tool. For instance, the core drilling tool may be a piston corer, a vibracorer, a rotary corer, a push corer, a percussion drill, a diamond coring drill string, and the like. While the measurement device may be used with any suitable core drilling tool, it is envisaged that, in some embodiments, the measurement device may be used with a core drilling tool during core sample recovery. Preferably, the measurement device may be used with a core drilling tool comprising an inner tube. The measurement device may be any suitable multi-tube core barrel. For instance, the core drilling tool may be a double-tube core barrel, a triple-tube core barrel, or the like.

[0009] In use, it is envisaged that the measurement device may be associated with the inner tube of a multi-tube core barrel. In an embodiment of the invention, the measurement device may be associated with the backend assembly of an inner tube. It will be understood that the term “backend assembly” (also referred to as a “head assembly”) is intended to refer to certain components of the inner tube of the core drilling device, such as, but not limited to, the spindle bearing assembly, the inner tube cap assembly, the core lifter assembly and so on. The measurement device may be associated with any suitable portion of the inner tube or the backend assembly. For instance, the measurement device may be associated with the inner tube, the spindle bearing assembly or a component thereof, or the inner tube cap assembly or a component thereof. Preferably, however, the measurement device may be associated with a portion of the backend assembly such that the measurement device remains fixed in relation to the inner tube while coring. In an embodiment of the invention, the measurement device may be associated with a lock collar configuration. In a preferred embodiment of the invention, the measurement device may be associated with the spindle bearing assembly of the backend assembly.

[0010] Preferably, the measurement device is adapted for removable connection to, or retention in, the backend assembly of the core drilling tool. The measurement device may be removably connected to or retained in the backend assembly of the core drilling tool by any suitable means. For instance, the measurement device may be removably connected to or retained in the backend assembly by frictional engagement, or by providing complementary screw- threaded portions, press fittings, snap fit features, male-female connectors, or combinations thereof.

[0011] The measurement device may replace one or more components or parts of the backend assembly. Preferably, the measurement device may replace and function as one or more components of the backend assembly. It will be understood that the term “function” is intended to refer to the purpose or operation of that component within the backend assembly, that is, the measurement device will effectively function as the component it is replacing in addition to comprising the one or more data acquisition portions housed within. The measurement device may replace and function as any suitable component of the backend assembly. For instance, the measurement device may replace and function as one or more components of the spindle bearing assembly or the inner tube cap assembly. In a preferred embodiment of the invention, the measurement device may replace and function as one or more components of the spindle bearing assembly. The measurement device may replace and function as any suitable component of the backend assembly. For instance, suitable components may include a bearing, a bushing, a lock nut, a valve, a washer, a cap, and the like. Preferably, however, the measurement device may replace a component of the backend assembly such that the measurement device remains fixed in relation to the inner tube while coring. [0012] The measurement device may replace one or more components or parts of the backend assembly. The components or parts of the backend assembly being replaced may be of any suitable type, for instance, the components may be an original equipment manufacturer part, a genuine part, an aftermarket part, or the like. Alternatively, the components or parts of the backend assembly being replaced may be a modified part, a remanufactured part, a refurbished part, or the like. However, it will be understood, that the type of part may vary depending on a number of factors, such as whether the core drilling tool is new or second-hand, user preferences and the type of part.

[0013] The measurement device may be of any suitable size. However it is envisaged that the measurement device may be of sufficient size so as to be received and retained within the inner tube of a core drilling tool without further modification of the core drilling tool. Preferably, the measurement device is of sufficient size to fit within the backend assembly of the core drilling tool. However, it will be understood that the size of the measurement device will vary depending on a number of factors, such as the type, configuration and size of the one or more data acquisition portions and the type, configuration and size of the core drilling tool.

[0014] The measurement device comprises one or more data acquisition portions. The one or more data acquisition portions may be of any suitable type. For instance, the one or more data acquisition portions may be a data logger, a microelectromechanical system (MEMS), a miniaturised electronic component, a micro-mechanical structure, a sensor array, sensor elements, a microsensor, transducer packages, and the like. Preferably, the one or more data acquisition portions comprise miniaturised electronic componentry.

[0015] Preferably, the data acquisition portion may comprise one or more of a detecting portion, a data processing unit and a data storage unit. In a more preferred embodiment the data acquisition portion may comprise a detecting portion, a data processing unit and a data storage unit. In some embodiments of the invention, the data acquisition portion may be associated with, or comprise, a power source. In some embodiments of the invention, the data acquisition portion may be associated with, or comprise, a communication portion. [0016] In an embodiment of the invention, the one or more data acquisition portions may be self-contained. In this instance, each data acquisition portion may comprise a detecting portion, a data processing unit, a data storage unit and a power source. In an alternative embodiment of the invention, two or more data acquisition portions may be interconnected. In this instance, it is envisaged that the two or more data acquisition portions may share one or more components such as a data processing unit, a data storage unit, a power source, or a communication portion. It is envisaged that, in use, where two or more data acquisition portions may be connected to a common component, the individual data acquisition portions may not be provided with this type of component. Alternatively, the individual data acquisition portions may also be provided with this type of component.

[0017] The data acquisition portions may comprise a detecting portion. Any suitable detecting portion may be used. For instance, the data acquisition portion may comprise a navigation or orientation sensor (such as a magnetometer, an accelerometer, an inertial navigation system, an inclinometer, a gyroscope, etc.), a temperature sensor, a magnetic field sensor (such as a magnetometer), a pressure sensor, a sound pressure level sensor, a vibration sensor, an inductive RPM sensor, a depth gauge or the like. However, it will be understood that the type of detecting portion may vary depending on a number of factors, such as the type of core drilling tool and the purpose of the survey. For instance, the measurement device may be used to obtain data about the geometries of the geology, the nature and properties of the rock surrounding the borehole, the conditions of the borehole, the operation of the core drilling tool and drilling progress, the orientation and properties of the core sample, core recovery parameters, and the like.

[0018] In an embodiment of the invention, one or more data acquisition portions may obtain any suitable data about the borehole and/or the core drilling tool, such as borehole temperature, the instrumentation working temperature, the core drilling tool temperature, the temperature of the rock, and combinations thereof. Preferably, the one or more data acquisition portions may obtain data about the temperature of the rock, the depth at which the temperature data was obtained and the orientation of the core sample at the time the temperature data was obtained. In use, it is envisaged that this information may aid in design of the mine in terms of ventilation requirements.

[0019] The data acquisition portion may comprise one or more data processing units. Any suitable data processing unit may be used. For instance, the data processing unit may be a microprocessor, an integrated circuit, a chip, a microchip, a microcontroller, a system on a chip, and the like. In use, it is envisaged that the data processing unit may be used to control the operation of the data acquisition portion. For instance, the data processing unit may be used to receive data from the one or more detecting portions, provide instructions to the one or more detecting portions, process the received data, store the processed and unprocessed data in a data storage unit, transmit the processed and unprocessed data to an external computing device or a user interface, receive instructions from an external computing device, interact with adjacent data acquisition portions, and the like.

[0020] The measurement device may comprise a data processing unit associated with the one or more data acquisition portions. In this embodiment, it is envisaged that the data processing unit of the data acquisition portion may be a different type or may control different operations to the data processing unit of the measurement device. For instance, the data processing unit of the measurement device may control interactions with an external computing device and may transmit instructions to the data processing units of the individual data acquisition portions, whereas the data processing units of the individual data acquisition portion may control the operation of the detecting portions. In an alternative embodiment of the invention, the data processing unit of the measurement device may perform as a back-up or reserve device.

[0021] The measurement device may comprise a power source electrically connected to the one or more data acquisition portions. Alternatively, each data acquisition portion may be self-contained and comprise a power source. Any suitable power source may be used. Preferably, the power source may be a battery. Any suitable type of battery may be used, for instance the battery may be chargeable or non-rechargeable. In an embodiment of the invention, the battery may be a non- rechargeable lithium battery. In an embodiment of the invention, a bank of batteries may be used. In an alternative embodiment of the invention, a single battery may be used. Preferably the battery may be an extended capacity battery. In this instance, it is envisaged that an extended capacity battery may last at least six months, up to 12 months, up to two years. However, it will be understood that the capacity of the battery may vary on a number of factors, such as usage of the measurement device, the type of detecting portion used and the data processing requirements. In other embodiments of the invention, the measurement device may draw electrical power from another source, such as mains power, a generator, one or more photovoltaic cells or the like, or a combination thereof.

[0022] In an embodiment of the invention, the power source may comprise a power converter. In this instance, the power converter may detect an output load and operate in an active mode delivering power to the measurement device or may enter a low-power stand-by mode. Alternatively, the power converter may change from a low-power stand-by mode to an active mode upon receipt of a signal from a data processing unit, an external computing device, a detecting portion, a borehole or drilling event, a timer, and the like.

[0023] The data acquisition portion may comprise a data storage unit. In use, it is envisaged that the data storage unit may store processed and unprocessed data, one or more predetermined rules relating to the task to be performed, the pattern of data acquisition based on the data being acquired, training data, programs and algorithms for the data processing units, etc.

[0024] The measurement device may comprise a data storage unit associated with the one or more data acquisition portions. In this embodiment, it is envisaged that the data storage unit of the data acquisition portions may store different information to the data storage unit of the measurement device. For instance, the data storage unit of the data acquisition portion may store information such as instructions relating to the control of the detecting portions and unprocessed data received from the detecting portions, whereas the data storage unit of the measurement device may store information such as algorithms, training data, etc. used by the data processing unit. In an alternative embodiment of the invention, the data storage unit of the measurement device may perform as a back-up or reserve device.

[0025] The one or more data acquisition portions may be associated with a communication portion. The data acquisition portion may be associated with a communication portion by any suitable means. For instance, the communication portion may be physically connected to the data acquisition portion (for instance, by being built into the data acquisition portion or by being attached to the data acquisition portion via one or more cables, wires, cords or the like). In other embodiments of the invention, the data acquisition portion and the communication portion may be in wireless communication with one another, such as by Wi-Fi, Bluetooth or the like.

[0026] The communication portion may be of any suitable form, although in a preferred embodiment of the invention the communication portion comprises a transceiver. In use, it is envisaged that the communication portion may send and/or receive data from the one or more detecting portions, send instructions from the data processing units to the one or more detecting portions, transmit the processed and unprocessed data to an external computing device or to a user interface, receive instructions from an external computing device, interact with adjacent data acquisition portions, and the like.

[0027] The communication portion may provide an interface between the data processing units of the one or more data acquisition portion and an external computing device or user interface. The communication portion of the data acquisition portions and the external computing device may be in electronic communication with one another. The communication portion of the data acquisition portions and the external computing device may be in electronic communication with one another in any suitable manner. For instance, the communication portion may be physically connected to the external computing device or user interface (for instance by being attached to the external computing device via one or more cables, wires, cords, or the like), or in wireless communication with the external computing device (for instance, by Wi-Fi, Bluetooth, or the like). The communication portion may be located in relatively close proximity to the external computing device or may be positioned remotely from the external computing device.

[0028] The communication portion may provide an interface between the data processing units of adjacent data acquisition portions. The communication portions of adjacent data acquisition portions may be in electronic communication with one another. The communication portions of adjacent data acquisition portions may be in electronic communication with one another in any suitable manner. For instance, the communication portions may be physically connected to one another (for instance by being attached to the communication portions via one or more cables, wires, cords, or the like), or in wireless communication with one another (for instance, by Wi-Fi, Bluetooth, or the like).

[0029] The measurement device comprises a housing portion configured to receive and retain the one or more data acquisition portions. The housing may be configured to receive the one or more data acquisition portions by any suitable means. For instance, the one or more data acquisition portions may be integrated into the housing portion during fabrication of the housing. Alternatively, the one or more data acquisition portions may be attached to a surface of the housing portion.

In a preferred embodiment of the invention, the housing portion may comprise a receiving portion such as a compartment, a cavity, a groove, a recess, or the like configured to receive the one or more data acquisition portions.

[0030] The receiving portions may be located in any suitable portion of the housing portion. For instance, the receiving portions may be in the form of a cavity located within the body of the housing portion, a compartment formed in an external surface of the housing portion, a recess formed on a surface of a bore of the housing portion, and the like. However, it will be understood, that the position of the receiving portion may vary depending on a number of factors, such as the size, shape and configuration of the data acquisition portion, the size, shape and configuration of the housing portion, the type of sensor and so on.

[0031] Preferably, the receiving portions may be in the form of one or more cavities located within the body of the housing portion. In use, it is envisaged that positioning the data acquisition portions in the body of the housing portion may assist the data acquisition portions in withstanding the high level forces during a drilling cycle, reduce exposure of the data acquisition portions to fluids, water, debris etc. during a drilling cycle and fix the position of the data acquisition portions relative to the inner tube of the core drilling tool.

[0032] The housing portion may comprise one or more portions. In an embodiment of the invention, the housing portion may be formed as a unitary structure. In an alternative embodiment of the invention, the housing portion may be formed from two or more portions. In this instance, it is envisaged that the two or more portions may be removably connected to one another. The two or more portions may be removably connected by any suitable means. For instance, the two or more portions may be retained in removable connection by frictional engagement, or by providing complementary screw-threaded portions, press fittings, snap fit features, male-female connectors, or combinations thereof. In use, it is envisaged that a sealing member, such as an O-ring, a gasket, or the like may be positioned between the two or more portions to reduce or eliminate the ingress of water and debris into the housing portion. In an embodiment of the invention, the housing portion may be configured to allow the housing portion to equalise pressure therein during drilling. For instance, the housing portion may be provided with valves, regulators, ports, vents, diaphragms, or the like to equalise pressure during drilling.

[0033] In an embodiment of the invention, the housing portion may further comprise a lid portion adapted for removable attachment thereto, and specifically for removable attachment to the body portion of the housing portion. The lid portion may be of any suitable size or configuration. Preferably, however, the lid portion is of sufficient size, shape and configuration to close the housing portion. It is envisaged that, in use, removing the lid portion may enable access to an internal compartment of the housing portion. Alternatively, removing the lid portion may enable a user to replace a damaged or worn lid portion where the lid portion may be abutted by a rotating portion of the backend assembly. In an alternative embodiment of the invention, the lid portion may comprise one or more data acquisition portions. In this instance, it is envisaged that the housing portion may be provided with different data acquisition portions by replacing the lid portion. In some embodiments of the invention, the lid portion may comprise or include a wear surface. [0034] The lid portion may be provided with one or more apertures. In use, it is envisaged that an external antenna associated with a communication portion of the measurement device may be passed at least partially through an aperture in the lid portion. Alternatively, the lid portion may be fabricated from a non-metallic material.

In use, it is envisaged that the lid portion may be fabricated from a non-metallic material for wireless transmission purposes.

[0035] The housing portion may be fabricated from any suitable material or combinations of material. Preferably, the housing portion may be fabricated from a material that enables the housing to withstand the high level forces, such as hydrostatic pressures, during a drilling cycle. For instance, the housing portion may be fabricated from metal or metal alloy, such as, but not limited to, steel or steel alloys (such as hardened steel, mild steel stainless steel, alloy steel, etc.), aluminium, a polymeric material, a ceramic material, or the like. However, it will be understood that the type of material may depend on a number of factors, such as the nature and properties of the rock surrounding the borehole, the type and configuration of core drilling tool, and the function of the component of the backend assembly being replaced. In an embodiment of the invention, the housing portion may be fabricated from the same type of material as other components of the backend assembly. In an alternative embodiment of the invention, the housing portion may be fabricated from a different type of material as other components of the backend assembly.

Preferably, however the housing portion may be fabricated from a type of material that does not affect the original function of the component being replaced or the operation of the core drilling tool.

[0036] The housing portion of the measurement device may be of any suitable size, shape or configuration. Preferably, the size, shape and configuration of the housing portion may be substantially the same as the size, shape and configuration of the measurement device. In an embodiment of the invention where the measurement device may replace one or more components of the backend assembly, it is envisaged that the size, shape and configuration of the housing portion of the measurement device may be substantially the same as the size, shape and configuration of the one or more components of the backend assembly.

However, it will be understood that the size, shape and configuration of the housing portion of the measurement device may vary depending on how the housing portion may be configured to receive the one or more data acquisition portions. However, it will be understood that the size, shape and configuration of the housing portion of the measurement device must not affect the function of the component it is replacing in the backend assembly.

[0037] In an embodiment of the invention, the housing portion of the measurement device may be substantially the same as one or more components of the spindle bearing assembly. For instance, the housing portion of the measurement device may be substantially the same external size and shape as a spindle, a valve, a washer, a bearing, a bushing, a spring, or a lock nut. In a preferred embodiment of the invention, the housing portion of the measurement device may be substantially the same as the spindle bushing of the spindle bearing assembly. In use, it is envisaged that the measurement device of the present invention may replace the spindle bushing of a backend assembly of a core drilling tool without affecting the original function of the spindle bushing or the operation of the core drilling tool. For instance, the measurement device may replace and function as a spindle bushing of a backend assembly of a core drilling tool, that is, it would effectively function as a spindle bushing, but would also include one or more data acquisition portions therein.

[0038] In an embodiment of the invention, the housing portion of the measurement device may be substantially the same as one or more components of the inner tube cap assembly. For instance, the housing portion of the measurement device may be substantially the same external size and shape as an inner tube cap, a check valve, a grease cap, or an inner tube adapter. In a preferred embodiment of the invention, the housing portion of the measurement device may be substantially the same as the check valve of the inner tube cap assembly. In a yet further embodiment of the invention, the housing portion of the measurement device may be substantially the same as the grease cap of the inner tube cap assembly. In use, it is envisaged that the measurement device of the present invention may replace a component of the inner tube cap assembly of a backend assembly of a core drilling tool without affecting the operation of the core drilling tool. For instance, the measurement device may replace and function as a grease cap of an inner tube cap assembly of a backend assembly, that is, it would effectively function as a grease cap but would also include one or more data acquisition portions therein.

[0039] In an embodiment of the invention, the housing portion may be provided with a body portion comprising one or more cavities located there within to receive the one or more data acquisition portions and a removable lid portion to close the housing portion (or, more specifically, to close the one or more cavities in order to reduce or eliminate the possibility of the unwanted or accidental removal of the one or more data acquisition portions). However, it will be understood that, the configuration of the one or more cavities in the housing portion and/or the lid portion do not affect the function of the component of the backend assembly being replaced or the operation of the core drilling tool.

[0040] In an embodiment of the invention, the measurement device may acquire and/or process data autonomously. In a further embodiment of the invention, the measurement device may acquire and/or process data semi-autonomously. In this embodiment, it is envisaged that the measurement device may be adapted to be controlled remotely by an operator. The operator may control the measurement device using any suitable technique. Preferably, the operator may control the measurement device remotely. In this embodiment of the invention, it is envisaged that a wireless connection (i.e. a wireless transmitter) may be provided between the operator and the measurement device. Thus, the operator may be located remotely to the measurement device. In some embodiments, a remote operator may be provided with a user interface (such as a screen or other display device) that allows the operator to view and monitor the operation of the measurement device. In these embodiments, the remote operator may be capable of intervening in the operation of the measurement device at any time, for instance, to provide a new pattern of data acquisition, turn on/off different data acquisition portions, to provide reference or training data, updated rules or instructions, and so on. It is envisaged that the remote operator may be able to switch the measurement device between being operator controlled and being operated autonomously.

[0041] In some embodiments of the invention, the measurement device may be operated entirely autonomously. In this embodiment, one or more data processing unit of the measurement device may be provided with one or more predetermined rules relating to the task to be performed, the pattern of data acquisition based on the data being acquired, training data, or any suitable combination thereof. Thus, it is envisaged that the measurement device may be operated solely by one or more data processing units of the measurement device (and the rules contained therein). In this embodiment, it is envisaged that no human operator may be required. In some embodiments, changes in the operation of the measurement device may be made in response to one or more operating factors, such as, but not limited to, fluid flow, drill pipe movements/rotations and so on.

[0042] The one or more data acquisition portions of the measurement device may be configured to acquire data according to any suitable pattern. For instance, data may be acquired at regular or irregular intervals of time, at pre-determined time intervals, in response to detecting a trigger signal, continuously, etc. Preferably, the one or more data acquisition portions of the measurement device are configured to acquire data continuously. In an embodiment of the invention, each of the one or more data acquisition portions may be configured to acquire data according to the same pattern. In an alternative embodiment of the invention, each of the one or more data acquisition portions may be configured to acquire data according to different patterns. It will be understood that data acquisition pattern may vary depending on a number of factors, such as the type of sensor collecting data, the operation of the core drilling tool and drilling progress, the nature and properties of the rock surrounding the borehole, and the like.

[0043] The frequency at which the one or more data acquisition portions of the measurement device may acquire data may be changed from a first pattern to a second pattern. For instance, the one or more data acquisition portions of the measurement device may be configured to acquire data continuously in a first pattern and configured to acquire data at predetermined time intervals in a second pattern. It is envisaged, that in use, an external computing device or the data processing units of the one or more data acquisition portions may change the pattern of data acquisition. The pattern of data acquisition may be changed to conserve power, conserve memory storage, increase or decrease data acquisition at a point in time or location, and the like. [0044] The acquired data may be processed to identify one or more data points that might indicate the core has been broken. The acquired data may be processed using any suitable means. For instance, the external computing device or the data processing unit of the one or more data acquisition portions may compare a first data point taken at a first time period with a second data point taken at a second time period. The data points may be taken at and/or over any suitable time period. For instance, the external computing device or the data processing unit may compare data points over a 1 second interval, a 10 second interval, a one minute interval, a one hour interval, or any suitable combination thereof. However, it is understood that the time period may vary depending on a number of factors, such as the type of data being acquired, the type of sensor being used, the purpose of the survey, the nature and properties of the rock surrounding the borehole, and the like. Preferably, however, sufficient data points may be compared in order to observe and identify changes in the operation of the core drilling tool and drilling progress which might indicate the core has broken. For instance, the one or more data points may include cessation of core drilling tool rotation, cessation of drilling fluid flow, a lack of vibration by the fact drilling has completed, and upward motion of the inner tube when breaking the core, and the like.

[0045] The acquired data may be processed to correct and linearize the data prior to storage. For instance, pressure data may be corrected for temperature, relative orientation of the device tagged with the time interval at which it was recorded, analogue data converted to digital data, and the like.

[0046] As previously stated, the measurement device or a component thereof may transmit processed and/or unprocessed data to an external computing device or a user interface. The external computing device or user interface may be capable of displaying the data received from the measurement device, storing the data received from the measurement device, processing the data received from the measurement device, sending instructions to the measurement device, and any suitable combination thereof. The external computing device or user interface may be of any suitable form. Preferably, however, the external computing device or user interface comprises a display portion adapted to display the information in human readable form thereon. Thus, for instance, the external computing device or user interface may comprise a computer, computer tablet, mobile telephone, distributed control system (DCS), a screen, a display device, a terminal, a hand-held device, or the like.

[0047] In another aspect, the present invention relates broadly to a method of obtaining in situ core orientation data using the measurement device according to the first aspect.

[0048] Therefore the present invention provides a number of advantages over the prior art. For instance, use of the present invention reduces the chance of mechanical failure of the core drilling tool as extension tubes are no longer required to be added to the outer tube of the core drilling tool to compensate for the added length of alternative commercially available measurement devices in the inner tube.

In addition, the present invention is a reduced cost solution which enables the user to continue to use off-the-shelf parts in the inner tube rather than replacing the entire backend assembly or substantial portions of it with a proprietary assembly containing a measurement device.

[0049] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0050] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0051] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0052] Figure 1A illustrates an exploded view of a backend assembly for a core drilling tool; [0053] Figure 1 B illustrates an assembled view of a backend assembly for a core drilling tool; and

[0054] Figure 2 illustrates an exploded view of a spindle bushing according to an embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

[0055] In Figure 1 A and 1 B, an exploded view (1 A) and an assembled view (1 B) of a commercially available backend assembly for a core drilling tool as used in the art is illustrated. Backend assembly 100 comprises a spearhead assembly (12), a latching mechanism (14), a landing shoulder (16), a spindle assembly (18) and inner tube cap assembly (20). Spindle assembly (18) comprises a measurement device in the form of a spindle bushing (10).

[0056] In Figure 2, an exploded view of a measurement device 10 in the form of a spindle bushing according to an embodiment of the invention is illustrated. Measurement device 10 comprises a housing portion (30), a lid portion (32), data acquisition portions (36) and a power source (38). Lid portion (32) is screw threadably engaged with housing portion (30) and comprises apertures (40) for receiving external antennae (42) associated with a communication portion of the data acquisition portions (36). Data acquisition portions (36) and power source (38) are positioned in receiving portions (44) located in the body of the housing portion (30).

[0057] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0058] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations. [0059] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.