This invention relates to machine operations and management systems including operating and maintaining machines . The invention has particular application to machine operations and management systems for remotely operated machines (or "operatorless" machines ) . The invention is particularly suited to machine operations in mining, quarrying, and civil construction operations where heavy machinery is used and where downtime is costly .

Various machine maintenance systems have been used to keep machines operating ef ficiently with a view to avoiding breakdowns . Such systems are commonly referred to as planned maintenance systems or scheduled maintenance systems . Such systems are useful for machinery or components which are subj ect to a constant load or loads which increase and decrease steadily . However, they are less suitable for machines and machine components which are subj ect to sudden increases and decreases in loads and especially components which are subj ect to intermittent shock loads which can lead to sudden component failure .

Preventative maintenance plays an important role in maximi zing the performance of machinery and equipment . In some cases , maintenance can be scheduled at regular intervals such as days , operating hours , or kilometres . However, for equipment that is subj ect to a wide range of operating conditions , wear rates and maintenance requirements can be highly variable and irregular .

Maintenance on some machinery and equipment may be anticipated and scheduled by directly inspecting the equipment as it wears . For example , a rotary drill bit may be inspected to examine the condition of the cutting structure and bearings . But direct inspection is not always practical for a variety of reasons . The equipment may be inaccessible , no sensors may be available to measure the necessary elements , or no operator is on site to regularly inspect the equipment ( as with autonomous machinery) . In such cases , it would be advantageous to have the ability to accurately estimate failure using measurements directly and indirectly related to the equipment and replace the machine or machine component before failure .

The present invention is aimed at repairing or replacing machines or machine components ahead of failure and especially ahead of sudden failure so that the machine or machine component can be replaced before failure and machine downtime can be avoided or at least reduced . In that respect , where machines are "driven" or "operated" remotely, a repair crew may be many hours travel away from the machine so there is advantage in being able to estimate a failure point sufficiently accurately so that replacement or repair can be scheduled ahead of failure .

The present invention achieves the desired result for a working machine or machine component by determining a relationship between failure of like machines or failure of a component of a like machine from historical data relating to one or more parameters and analysing real time corresponding data for the working machine and replacing or repairing the machine or machine component ahead of failure . Thus , the invention in some aspects provides a system and/or a method which dynamically estimates the remaining li fe of a machine or machine component while in other aspects the invention incorporates the system or method to dynamically estimate the remaining li fe of a machine or machine component . While various machines can be subj ected to loads which can lead to sudden component failure , drilling rigs and especially downhole components of drilling rigs are particularly subj ect to sudden load changes and in some cases sudden shock loads . More particularly, drilling rigs used for drilling blast holes are subj ect to sudden load changes and shock loads because of the changing nature of strata being drilled . Consequently the invention will be described with reference to such application although it is to be understood that the invention has application to other machines and machine components used in various construction operations . For example , bulldozers working in some terrain may be subj ect to impact loads or shock loads as well as general abrasive wear and such loads may cause sudden failure of track rollers , drive sprockets or other components . While the present invention would have application to such machines , the formulae referred to herein may not be appropriate to such machines although the concepts would apply mutatis mutandis .

Downhole drill bits can fail for reasons other than abrasive wear, for example , drill bit crown fracture , drill bit body fracture , drill bit bearing failure , drill bit tooth fracture , or drill stem fracture . While abrasive wear can be accommodated to some extent according to a scheduled maintenance system or a scheduled replacement system, many other failure types cannot because failure is not simply a function of torque , angular drill stem velocity or download on the drill bit although in some cases such parameters may have an ef fect .

In the case of downhole drill bits , presently known systems commonly referred to as Measure While Drilling (MWD) systems record various drill parameters including pulldown force , rotation speed, rotation torque , feed rate , etc . Those parameters are typically measured by suitable sensors and onboard computer systems and the relevant data for those parameters is recorded . Typically, a dataset of drill parameters is recorded at speci fied regular intervals either as time intervals or depth intervals , for example every 250mm . That type of data is generally referred to herein as historical data even though such data may have been collected very recently and perhaps provides data for as little as one drill hole .

With the foregoing in view, the invention resides broadly in a system for predicting failure of a machine or machine component including : means for storing or inputting historical data for predetermined parameters relating to failure of one or more similar machines or machine components ; means for determining a relationship between failure or li fe of the one or more similar machines or machine components and said historical data ; means for obtaining data relating to predetermined parameters of the machine or machine component to be predicted on a real time basis ; and means for using the relationship determined for the similar machine or machine component and the data obtained for the machine or machine component to be predicted to estimate the point of failure of the machine or machine component .

In a related aspect , the invention resides broadly in a maintenance system for a machine or machine component including : means for storing or inputting historical data for predetermined parameters relating to failure of one or more similar machines or machine components ; means for determining a relationship between failure or li fe of the one or more similar machines or machine components and said historical data ; means for obtaining data relating to predetermined parameters of the machine or machine component to be maintained on a real time basis ; and means for using the relationship determined for the similar machine or machine component and the data obtained for the machine or machine component to be maintained to estimate the point of failure of the machine or machine component ; and replacing or repairing the machine or machine component before the estimated point of failure .

In some cases , although a relationship may have been determined for a similar machine or machine component , that relationship may be modi fied to estimate the point of failure of the machine or machine component to be maintained . For example , it may be desirable to ignore data above or below a selected threshold or it may be beneficial to simpli fy the data relating to one or more parameters in some cases on account of cost or some other factor . Such possible variations may apply to any of the di f ferent aspects of the invention described herein .

In another aspect , the invention resides broadly in a method of predicting failure of a machine or machine component including : obtaining historical data for predetermined parameters relating to failure of one or more similar machines or machine components ; determining a relationship between failure or li fe of the similar machines or machine components and said historical data ; obtaining data relating to the same predetermined parameters of the machine or machine component to be predicted; and using the relationship determined for the one or more similar machines or machine component and the data obtained for the machine or machine components to be predicted to estimate the point of failure of the machine or machine component .

In a related aspect , the invention resides broadly in a method of maintaining a machine or machine component including : obtaining historical data for predetermined parameters relating to failure of one or more similar machines or machine components ; determining a relationship between failure or li fe of the similar machines or machine components and said historical data ; obtaining data relating to the same predetermined parameters of the machine or machine component to be maintained; and using the relationship determined for the one or more similar machines or machine component and the data obtained for the machine or machine components to be maintained to estimate the point of failure of the machine or machine component ; and replacing or repairing the machine or machine component before the estimated point of failure .

The point of failure may be a period or a time or any other suitable reference method such as number of revolutions of a drill stem or drill bit etc .

Preferably, the data for the machine or machine component is continuously collected . In such form of the invention, it is also preferred that the data continuously collected be continuously used to provide a continuously updated estimation of the point of failure .

The term "continuously" includes collecting data in discrete spaced apart sets , for example , once every minute or once every 200mm of drilling or once every revolution or the like . Preferably, data from the machine or machine component is input on a real time basis thereby allowing the estimated failure point to be continuously updated .

In yet another aspect , the invention resides broadly in a system or method of predicting failure of a drill bit component of a machine including : inputting data relating to one or more predetermined parameters of the machine relating to energy; calculating the rate of change in energy 8E between sequential datasets according to the formula 8E = — (where AE is the change in energy between the data sets and Ax is a time unit or the change in a continuous parameter such as time , distance or number of drill stem revolutions . summing the Energy E for datasets in which 5E is greater than a predetermined value to give accumulated Impulse Energy Z IE ; and comparing the accumulated impulse energy with a predetermined estimated failure point .

In a related aspect , the invention resides broadly in a system or method of maintaining a machine or a drill bit component of a machine including : inputting data relating to one or more predetermined parameters of the machine relating to energy E ; calculating the rate of change in energy 8E between sequential

AE datasets according to the formula 8E = — (where AE is the change in energy between the data sets and Ax is a time unit or the change in a continuous parameter such as time , distance , or number of drill stem revolutions . summing the Energy E for datasets in which 5E is greater than a predetermined value to give accumulated Impulse Energy Z IE ; and comparing the accumulated impulse energy with a predetermined estimated failure point ; and replacing the drill bit before the estimated failure point .

In yet another aspect , the invention resides broadly in a method of predicting failure of a drill bit component of a machine including : inputting data relating to predetermined parameters of the machine including pulldown force ( L ) , bit area (A) , drill stem rotation speed (R) , drill stem torque ( T ) , and penetration rate ( P ) ; calculating energy for each dataset according to the formula

E = LAR/P + T calculating the change in energy 8E between sequential datasets according to the formula 8E = — ;

Ax summing the Energy E for datasets in which 5E is greater than a predetermined value to give accumulated Impulse Energy Z IE ; and comparing the accumulated impulse energy with a predetermined estimated failure point .

In a related aspect , the invention resides broadly in a method of maintaining a machine or a drill bit component of a machine including : inputting data relating to predetermined parameters of the machine including pulldown force ( L ) , bit area (A) , drill stem rotation speed (R) , drill stem torque ( T ) , penetration rate ( P ) ; and calculating energy for each dataset according to the formula

E = LAR/P + T ; calculating the change in energy 8E between sequential datasets according to the formula summing the Energy E for datasets in which 5E is greater than a predetermined value to give accumulated Impulse Energy Z IE ; and comparing the accumulated impulse energy with a predetermined estimated failure point ; and replacing the drill bit before the estimated failure point .

In some cases the drill stem torque ( T ) will have very little ef fect on the energy calculation and consequently can be ignored or omitted whereupon the energy formula could be modified to E = LAR/P without any signi ficant ef fect . Similarly, in some cases other parameters might be insigni ficant and be omitted or ignored .

Preferably, the method includes replacing the drill bit at a predetermined period of time before the estimated failure point , or a predetermined number of revolutions or length of drilling before the estimated failure point .

Preferably, the rate of accumulation of impulse energy is determined by linear regression .

In still yet another aspect , the invention resides broadly in a method of determining an estimated failure point for a drill bit component of a machine , including : inputting historical data for one or more predetermined parameters relating to failure of a drill bit in a geographic location or geologic structure ; io determining from the inputted data a relationship between accumulated impulse energy and accumulated drill bit time worked; applying the relationship determined between accumulated impulse energy and accumulated drill bit time worked to estimate failure point of the drill bit .

In still yet another related aspect , the invention resides broadly in a method of maintaining a drilling machine including : inputting historical data for one or more predetermined parameters relating to failure of a drill bit in a geographic location or geologic structure ; determining from the inputted data a relationship between accumulated impulse energy and accumulated drill bit time worked; applying the relationship determined between accumulated impulse energy and accumulated drill bit time worked to estimate failure point of the drill bit ; and replacing the drill bit before the estimated failure point .

In still yet another aspect , the invention resides broadly in a method of determining an estimated failure point for a drill bit component of a machine , including : inputting historical data for one or more predetermined parameters relating to failure of a drill bit in a geographic location or geologic structure ; determining from the inputted data a relationship between accumulated impulse energy and accumulated drill bit time worked; applying the relationship determined between accumulated impulse energy and accumulated drill bit time worked to estimate a desired penetration rate or other operating parameter to achieve a desired end . Preferably, the method includes replacing the drill bit at a predetermined period of time before the estimated failure point , or a predetermined number of revolutions or length of drilling before the estimated failure point .

In still yet another related aspect , the invention resides broadly in a method of operating a drilling machine including : inputting historical data for one or more predetermined parameters relating to failure of a drill bit in a geographic location or geologic structure ; determining from the inputted data a relationship between accumulated impulse energy and accumulated drill bit time worked; applying the relationship determined between accumulated impulse energy and accumulated drill bit time worked to estimate a desired penetration rate or other operating parameter to achieve a desired end .

In yet another aspect the invention resides broadly in a system or method of operating a drilling machine where historical data relating to one or more selected parameters from the group consisting of Pulldown Force , Rotation Speed, Rotation Torque , Feed Rate and drill bit diameter has been collected for similar machines or machine components , and wherein a relationship between failure or li fe of the one or more similar machines or machine components and said historical data has been determined; and wherein real time data for an operating drilling machine or drill bit has been obtained and an estimated failure point of the operating drill bit has been estimated, the system or method including replacing the drill bit when the estimated failure point reaches a period which is less than a selected predetermined period . In such a system it is advantageous if the estimated failure point has been continuously updated during drilling, for example, by using MWD data .

In yet another aspect , the invention resides broadly in a system or method of predicting failure of a machine or machine component including : inputting data relating to one or more predetermined parameters of the machine relating to energy; summing the Energy E for datasets which relate to shock loads to give accumulated Impulse Energy S IE ; and comparing the accumulated impulse energy with a predetermined estimated failure point .

In such aspect , the shock loads may be determined or defined as loads where the energy is greater than a predetermined threshold or the change in energy within a predetermined period is greater than a predetermined threshold .

Such a method is believed to have application to downhole drill bits where some strata could be said to be "easy drilling" with low energy and little change over a long period . However, in other strata , high energy loads over a long period may be required and in still other strata , the loads might change suddenly and intermittently from a low load to a high load thereby causing sudden shocks .

In order that the invention may be more easily understood and put into practical effect, reference will now be made to an example of the invention in use wherein : Fig . 1 is a graphical representation of the accumulation of Impulse Energy ( as referred herein) throughout the li fe of a particular drill bit used in drilling multiple blast holes ;

Fig . 2 is a graphical representation of the accumulation of Impulse Energy throughout the li fe of seven di f ferent drill bits 41 to 44 and 46 to 49 drilling multiple blast holes ;

Fig . 3 is a graphical representation of Bit Li fe (Hours ) vs Impulse Accumulation Rate ( 5IE ) for the same seven drill bits 61 to 64 and 66 to 68 ) ;

Fig . 4 is a graphical representation of an example of how the Bit Performance Curve 69 can be used for an actively drilling bit ; and

Fig . 5 is a graphical representation of the example drill bit used in Fig . 4 after an additional seven hours of drilling .

In the example embodiment of the invention, operating parameters of a drill rig are continuously processed and evaluated to dynamically estimate the usable li fe of the drill bit component of the drilling rig so that the drill bit can be replaced at a desired time before failure . The analysis of speci fic drilling parameters yields criteria which, when compared to historical trends , is used to estimate a point of failure and then taking appropriate action before failure . The analysis is performed continuously all the time or continuously at discrete preset intervals while the drill bit is in use to calculate and adj ust the estimated point of failure based on the variable parameters . While the embodiment described relates to rotary drills and drill bits, and the invention can be used for other drilling components, for example, fixed cutter drill bits, DTH hammers and drill bits, raised bore cutters, shock subs, and drill rods, a similar process could be applied to other machines and machine components with measurable, variable loads and parameters which affect the rate at which such machines and components wear such as haul trucks, draglines, shovels, loading and hauling machinery, and power transmission whereby components prone to failure can be replaced before failure.

This embodiment of the invention in use provides a maintenance method and/or system or an operating method or system in which the remaining life of a rotary drill bit is estimated and the drill bit replaced before failure. The method uses the continuously measured operating parameters of a typical modern rotary drilling rig typically referred to as MWD (Measure While Drilling data) to estimate the total life (hours) of a drill bit and/or the life remaining in hours or any other suitable units. This embodiment also highlights significant events which adversely affect drill bit life.

MWD systems for drilling rigs typically record drill parameters which are common to most modern drills, including Pulldown Force, Rotation Speed, Rotation Torque, Feed Rate, etc. These parameters are typically measured by the drill's sensors and onboard computer control system and are recorded for each hole drilled at specified regular intervals, for example every 250mm.

In this embodiment drill MWD data is used to calculate Energy, AE identify high energy change events (— ) , and record the energy associated with those events (Impulse Energy) . The rate of accumulation of Impulse Energy throughout the li fe of a drill bit ( Impulse Accumulation Rate ) is calculated to estimate when a bit is going to fail based on the theory that bits fail largely because of high energy events .

In this embodiment two user-defined variables are selected to optimi ze the coefficient of determination (R2 ) for the Bit Performance Curve :

• Emax - The maximum Energy that can be calculated for one line of MWD data ; and

• 5E - The minimum energy change to define Energy as Impulse Energy .

Energy Calculation

Four parameters from the MWD data ( Pulldown, RPM, ROP, Torque ) and Bit Diameter are used to calculate the Energy for each dataset using the formula :

E= LAR/P+T

Where-. L = Pulldown (kN);

A = Bit Area (m2);

R = Rotation Speed (1/min);

P = Penetration Rate (mm/miri); and

T = T orque (kN ■ m) .

Impulse Energy

Impulse Energy is the name given to the energy associated with

AE high rate of energy change ( — ) between two sequential datasets .

AE

I f — exceeds a pre-defined value ( 5E ) , then E is recorded as

Impulse Energy ( IE ) .

Impulse Accumulation Rate Linear Regression is used to determine the rate of accumulation of Impulse Energy (TIE) vs the accumulation of Hours worked (ZH) . The slope of this line is the Impulse Accumulation Rate (5IE) which is used in the Bit Performance Curve.

In Fig. 1, it can be seen that the Impulse Energy of the bit rises sharply at 21 to 22 from 100MJ to 1100MJ in a very short time period, perhaps even instantaneously. That sharp rise is followed by subsequent sharp rises at 23 and 24 after a period of about 1.5 hours. These sharp rises represent events of shock load, which cause Impulse Energy to accumulate rapidly. The shallow rise from 26 to 27 over 10 hours shows a period of no shock load events, followed by another sharp rise from 27 to 28. When linear regression is performed on the accumulation of Impulse Energy, the slope of the line 31 defines the Impulse Accumulation Rate (5IE) .

As can be seen in Fig. 2, the drill bits that rapidly accumulate more Impulse Energy tend to drill fewer hours. For example, drill bit 41 accumulated 6200MJ of Impulse Energy and drilled 16 hours, whereas drill bit 49 accumulated 700MJ of Impulse Energy and drilled 48 hours. For each drill bit, linear regression is performed on the accumulation of Impulse Energy and the slope of the lines are the Impulse accumulation rates (5IE) for the respective drill bits 51, 52, 53, 54 56, 57, and 58.

As will be appreciated from Figs. 2 and 3, a plot of total Hours to failure vs Impulse Accumulation Rate has a negative correlation, indicating that bits with a higher Impulse Accumulation Rate will drill fewer hours. Linear regression of this data provides the Bit Performance Line (or curve) 69 shown in Fig. 3. The equation of the line 69 shown in Fig. 3 is: y = mx + b

Where-, y = Bit Life (hours); and x = Impulse Accumulation Rate;

In this example, the actual equation 71 of the line shown in Fig. 3 is determined to be: y = —0.0881% + 47.265

The Bit Performance Curve is used to predict the total usable life (hours) of an actively drilling bit.

It will be appreciated from Fig. 4 that as the bit is drilling, linear regression is continuously performed on the accumulation of Impulse Energy 81. The slope of the line 82 is used in the actual equation 71 to provide a continuing estimation of the final bit life 83.

In Fig. 4, sharp rises at 86 to 88 have caused a high Impulse Accumulation Rate 82 with a slope of 374.8. Thus, after 12 hours of drilling the estimated bit life 83 remaining is 14.2 hours (14.2 = -0.0881 * 374.8 + 47.265) .

As can be seen in Fig. 5, a shallow rise from 91 to 92 has allowed the Impulse Accumulation Rate 93 to decrease so that it now has a slope of 257.7. Thus, after 19 hours of drilling, the estimated bit life 94 is now 24.6 hours (24.6 = -0.0881 * 257.7 + 47.265) . Thus, the present invention provides a system and method for continuously updating the expected life of a drill bit during drilling thereby allowing the remaining life to be estimated and the drill bit replaced before failure. It is to be understood that the above has been given by way of illustration of the invention and that all such modi fications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as described herein .