NO20190959A1

NO20190959A1 - Method and system for generating a drilling pattern, and a rock drilling rig

Info

Publication number: NO20190959A1
Application number: NO20190959A
Authority: NO
Inventors: Pär Vörde; Andreas Andersson; Pär Härström; Per Turner
Original assignee: Epiroc Rock Drills Ab
Priority date: 2017-02-27
Filing date: 2019-08-06
Publication date: 2019-08-06
Also published as: CN110366629B; CN110366629A; AU2018223937A1; ZA201904662B; CL2019002430A1; WO2018156072A1; AU2018223937B2; SE541472C2; SE1750208A1; FI20195701A1; CA3050422A1

Description

METHOD AND SYSTEM FOR GENERATING A DRILLING PATTERN, AND A ROCK DRILLING RIG

Field of the invention

The present invention relates to rock excavation, and in particular to a method and system for generating a drilling pattern during rock excavation. The invention also relates to a rock drilling rig, as well as a computer program and a computer-readable medium that implement the method according to the invention.

Background of the invention

Rock excavation, in particular underground rock excavation, may be carried out using various techniques, where excavation using drilling and blasting technology is a commonly used method. The excavation may consist in the creation of a rock cavity having a predefined shape and geographical location. This may be the case, for example, when creating tunnels or other kinds of underground cavities. Excavation using drilling and blasting is, in general, carried out in a manner in which drilling is performed in rounds, where a round of holes is drilled to thereafter be loaded with explosives to blast the rock. Following removal of rock being detached by the blasting, a new round of holes are drilled to blast a subsequent portion of the cavity to be created. This is repeated until excavation of the desired cavity has been completed.

In order to achieve a rock excavation that results in a desired cavity being created, each round of holes are being drilled according to a drill plan, or drilling pattern, which essentially determines location, direction, length and possibly diameter of the holes to be drilled. The object of the drilling pattern being to create a cavity having a cross-sectional shape and geographical alignment that corresponds to the cavity the creation of which being the task at hand.

Cavities of this kind may be of various designs. For example, the cavity may be designed to have essentially the same cross-sectional appearance following an essentially straight line. However, as is oftentimes the case, properties of the cavity, e.g. in terms of cavity cross section and curvature, may vary along the length of the cavity. This may require utilization of different drilling patterns for different sections of the cavity to be excavated.

With regard to, for example, tunnels, but also other kinds of cavities, these are oftentimes associated with highly precise requirements regarding conformance with the desired cavity cross section and geographic alignment/extension. For example, lining such as concrete lining may be utilised, where over-break of rock result in an increased consumption of lining and oftentimes also an increase in the requirement of rock reinforcement. Insufficient breaking, under-breaking, on the other hand, may require additional drilling and blasting to obtain the desired cavity. Hence, welldesigned drilling patterns and subsequent drilling in accordance with the drilling patterns is essential in order to achieve the desired result.

Summary of the invention

It would be advantageous to achieve a method and system that may be utilised to obtain a drilling pattern for rock excavation that may reduce surplus rock when excavating a cavity in conformance with predetermined geographical alignment/extension.

According to the present invention, it is provided a method for generating a drilling pattern for excavating a cavity in rock, the drilling pattern determining holes to be drilled in a face of the rock, the determination of the holes to be drilled being a determination of location, direction and length of the holes to be drilled, the holes being arranged to be drilled by a drilling rig comprising at least one feed beam carrying a drilling machine, the at least one feed beam having a first end arranged to, during drilling, face the rock to be drilled and a second end being opposite to said first end. The method comprises:

- generating a drilling pattern comprising holes having a drillability, the drillability of said holes being determined when generating said drilling pattern by ensuring a manoeuvrability of said second end of said at least one feed beam in relation to surrounding rock.

The drilling pattern may be generated prior to excavation of the cavity commences.

The drilling pattern may comprise holes to be drilled subsequently to the generation of the drilling pattern.

The drilling machine may be slidable along the feed beam.

As was mentioned above, the drilling pattern being used in rock excavation using drilling and blasting technology is an important factor in order to achieve a cavity having a cross section and geographical extension that conforms to a high extent to the planned alignment of the cavity. Drilling patterns, also known as drill plans, define the location, position, of the holes to be drilled in a rock face of the rock to be excavated, and also the direction and length of the holes. The drilling pattern may also determine the diameter of the hole to be drilled, where e.g. holes along a periphery of the contour, i.e. cavity profile, outline or cross section, to be drilled may be of a different diameter than holes more to the centre of the rock portion to be excavated. Contour is used in the following as a representation of cavity profile/outline/cross-section.

The drilling pattern is generated on the basis of the contour/profile of the cavity to be created, and a plurality of consecutive rounds of drilling and blasting are in general required to create the desired cavity, such as a tunnel.

Drilling patterns may be generated in various manners as is known to the person skilled in the art, and embodiments of the invention may be utilised in combination with any such method. Drilling patterns are oftentimes generated beforehand, i.e. prior to excavation of the cavity commences, e.g. in a control/planning centre, to then be downloaded to the rock drilling rig for use in the excavation.

Rock excavation often results in surplus rock being broken, and this is also often necessitated by constructional constraints that hinders optimal positioning of a drilling rig/drilling machine used in the excavation, which thereby renders it difficult to drill holes that result in excavation without surplus rock being broken. Surplus cavity formed during tunnel excavation is oftentimes subject e.g. to subsequent concrete lining, where the surplus rock being broken also results in additional consumption of concrete e.g. in concrete lining operations and may also generate an increase in required rock reinforcement following blasting. Drilling patterns are in general designed to reduce the amount of surplus rock being broken, but it may not always be possible to drill completely according to the predetermined drilling pattern.

According to embodiments of the invention, the drilling pattern is generated following drilling and blasting of a previous round, and when generating the drilling pattern, this is designed to comprise holes having a drillability, i.e. the holes are to be drillable by the rock drilling rig. The drillability of the holes is determined by ensuring a manoeuvrability of the feed beam in relation to surrounding rock to ensure that the surrounding rock does not hinder positioning of the feed beam required to drill the hole. In particular, in order for a hole to be drillable, it is ensured that the rear end of the feed beam, i.e. the end facing away from the rock face during drilling, can be manoeuvred in relation to the surrounding rock to ensure that a hole can actually be drilled.

In this way, a drilling pattern can be generated that ensures that holes of the drilling pattern are also drillable in reality, so that adaptions of the drilling pattern during ongoing drilling of a round due to holes not being possible to drill can be reduced, which thereby may reduce the risk of over-breaking and/or under-breaking of rock resulting from adaptions of the drilling pattern during ongoing drilling.

According to embodiments of the invention, the manoeuvrability of the second end of the feed beam in relation to surrounding rock utilises a representation of the rock surrounding said second end. For example, manoeuvrability of the second end of the feed beam in relation to surrounding rock can be ensured when generating the drilling pattern utilising a representation of the cavity in a coordinate system of the cavity. Using the position of the drilling rig in this coordinate system, the manoeuvrability of the feed beam can then be determined using the representation of the cavity, where the rock outside the cavity contour in the representation of the cavity represents the surrounding rock

According to embodiments of the invention, a manoeuvrability of the second end of the feed beam in relation to surrounding rock when generating the drilling pattern is ensured utilising a representation of actual rock walls, resulting from blasting of one or more previous rounds of drilling, where the representation of the actual rock walls can be generated e.g. by one or more scanners, e.g. located on the drilling rig. In this way, manoeuvrability of the feed beam can be determined in relation to actually excavated rock, which, e.g. in case of over-breaking, may allow further manoeuvrability and thereby drilling of further/other holes than would be possible to drill according to the predetermined cavity contour.

According to embodiments of the invention, a manoeuvrability of the second end of the feed beam in relation to surrounding rock is determined utilising a representation of a cross section, contour, of the cavity at a distance from a representation of the face to be drilled substantially corresponding to the length of the feed beam. It is in general the second, i.e. rear, end of the feed beam that will impose limitations, and in this way manoeuvrability can be determined by determining the manoeuvrability of the second end in relation to the cavity contour prevailing at its location. A profile representing actually excavated rock may also be utilised.

Furthermore, in addition to taking into account the second(rear) end of the feed beam, further portions of the feed beam between the first end and the second end may also be taken into account when determining drillability. For example, in case there are protrusions in the rock along the length of the feed beam, manoeuvrability of the feed beam may be determined in relation to such protrusions as well.

The rock drilling rig may comprise a plurality of feed beams, each carrying a drilling machine, and the determination may be performed for the particular feed beam that is to drill an intended hole.

According to embodiments of the invention, the manoeuvrability of the feed beam is determined when the cross section, contour, of the cavity is narrowing in the direction of excavation, and/or a curvature of the cavity is changing. It is oftentimes in situations of these kinds that limitations regarding the manoeuvrability of the feed beam may have the most negative impact when drilling a drilling pattern where this manoeuvrability has not been accounted for.

According to embodiments of the invention, the manoeuvrability of the feed beam is determined when the cross section, contour, of the cavity is changing such that different drilling patterns are used for consecutive rounds of drilling and blasting.

According to embodiments of the invention, the manoeuvrability of the feed beam is determined when excavation of the cavity has progressed to an extent at least corresponding to the length of the feed beam.

According to embodiments of the invention, when generating the drilling pattern, a face contour is determined to represent the rock face to be drilled, the face contour constituting a cross section of the cavity in a navigation plane adjacent the rock face to be drilled is determined.

The drilling pattern can be determined as an aggregate drilling pattern comprising determination of a first drilling pattern for a first part of the face contour, and at least one second drilling pattern for at least one second part, different from the first part, of the face contour. A maximum hole length of holes of the first drilling pattern can be arranged to be longer than a maximum hole length of holes of the second drilling pattern.

The first part of the face contour can be determined using a first contour and a second contour, where the first contour is a representation of the cross section of the cavity at a distance from the face contour substantially corresponding to the length of the feed beam, and where the second contour is a representation of a cross section of the cavity at a distance from the face contour substantially corresponding to the maximum length of the holes to be drilled.

According to embodiments of the invention, the first part of the face contour is determined utilising interpolation between the first contour, which is located in one direction from the face contour and the second contour, which is located in another direction from the face contour in the plane of the face contour. The interpolation is made in the plane of the face contour. This first part of the face contour represents a part for which holes having a length determined by the distance between the face contour and the second contour can be drilled. For example, the maximum length of holes to be drilled in the round. Since the face contour defines the maximum surface to be drilled, the interpolation may be delimited also by the face contour so that the first part forms part of the face contour and does not extend outside the face contour even if this would be the result from the interpolation. In this way, in particular because of the use of the first contour, a part/portion of the face contour can be determined, where it can be ensured that the holes of the drilling pattern can be drilled to a desired, e.g. full length, without feed beam manoeuvring imposing limitations once drilling is started.

The method may be arranged to be utilised in situations where the interpolation results in the first part of the face contour will not comprise the full face contour.

The first part may further be determined utilising projection of the first contour and/or said second contour onto the face contour instead of utilising interpolation. In this way, the part of the face contour for which holes of full length are drilled can be reduced to, instead, increase the remaining part, for which, according to the below, holes of a reduced length is drilled. For example, this may be utilised when otherwise the remaining part of the face contour becomes undesirably small so it may e.g. be difficult to get room for further, or a desired number of, holes to be drilled in the remaining part.

With regard to the portion of the face contour for which holes having full length are not to be drilled, i.e. the remaining part of the face contour, it can be determined, e.g. on the basis of the width of this portion of the face contour and/or the number of holes to be drilled on this remaining portion, at least one intermediate contour between the face contour and said second contour, each of said at least one intermediate contours representing a cross section of the cavity at different distances from the face contour towards the second contour. These at least one intermediate contours are then used when generating a drilling pattern of said remaining portion of the face contour, and a drilling pattern is generated for different parts/portions of said face contour for each of said intermediate contours utilising said intermediate contour, respectively, and said first contour e.g. as described above using interpolation and/or projection. The holes of these at least one additional drilling pattern will hence have a shorter length than the holes of the first part of the face contour above. The reduced hole length in combination with the first contour ensures that also the remaining part of the face contour can be drilled using a drilling pattern where manoeuvrability of the feed beam is still ensured.

A drilling pattern encompassing the face contour can consequently be determined, where the drilling pattern is an aggregate of drilling patterns for different parts of the face contour. Further, when holes of drilling patterns for different parts of said face contour are located within less than a first distance from each other, thereby considered to have overlapping coverage of the rock to be drilled, holes of at least one of the drilling patterns can be omitted. For example, the hole having the shortest, or longest for that matter, length, can be arranged to be omitted.

It will be appreciated that the embodiments described in relation to the method aspect of the present invention are all applicable also for the system aspect of the present invention. That is, the system may be configured to perform the method as defined in any of the above described embodiments. Further, the method may be a computer implemented method which e.g. may be implemented in one or more control units of a rock drilling rig.

Further characteristics of the present invention and advantages thereof are indicated in the detailed description of exemplary embodiments set out below and the attached drawings.

Brief description of the drawings

Fig. 1 A-B illustrates an exemplary representation of a part of a tunnel to be excavated;

Fig. 2 illustrates an exemplary embodiment of a rock drilling apparatus in which embodiments of the invention may be utilised;

Fig. 3 illustrates an exemplary method according to embodiments of the invention;

Fig. 4 illustrates an exemplary method for reducing the risk that under-breaking of rock occurs;

Fig. 5 illustrates a further exemplary method according to embodiments of the invention for generating a drilling pattern.

Fig. 6 illustrates an exemplary representation of a part of a tunnel to be excavated, including contours utilised when generating a drilling pattern according to embodiments of the invention;

Fig. 7 illustrates determination of a contour for drilling of full-length holes, forming part of a rock face to be drilled;

Fig. 8 illustrates the cross sectional appearance of the contour for drilling of fulllength holes in relation to the rock face to be drilled;

Fig. 9 illustrates the cross sectional appearance of the contour for drilling of holes having a reduced length in relation to the rock face to be drilled;

Fig. 10 illustrates a method for determination of contours for drilling holes having a reduced length, the contours forming part of a rock face to be drilled;

Fig. 11 illustrates holes to be drilled from a face contour towards bottom contours according to embodiments of the invention;

Fig. 12 illustrates a method for increasing the cross sectional appearance of the contour for drilling of holes having a reduced length in relation to the rock face to be drilled;

Detailed description of exemplary embodiments

Embodiments of the invention will be exemplified in the following with reference to examples relating to excavation of a tunnel. Figs. 1 A-B illustrates an exemplary representation of a section of a tunnel to be excavated in rock. The tunnel may be any kind of tunnel for any suitable use, and e.g. comprise a tunnel forming part of a mine, or a tunnel for road or railway transport.

According to the example, the tunnel is represented by a tunnel line TL, which essentially is defined by points TLn-3, TLn-2... TLn+2 which may be interconnected. The extension, alignment, of the tunnel in the longitudinal direction may hence be obtained by interconnecting the tunnel line points. The disclosed section of the tunnel to be excavated represents a section of the tunnel about n tunnel line points into the tunnel. The tunnel line points are defined in a 3D-coordinate system being used in the excavation, e.g. a global coordinate system or a coordinate system local to the area of excavation, so that the desired tunnel can be excavated in conformity with the pre-planned tunnel alignment.

Any suitable number of tunnel line points may be used in the representation of the tunnel, where the number e.g. may depend on the length of the tunnel to be excavated, and any suitable, constant or varying, distance between the tunnel line points may be used, e.g. in dependence of curvature. For example, the distance between tunnel line points may represent the length of the longest holes to be drilled during a round for subsequent blasting. The length of the holes to be drilled may e.g. correspond to the length along a feed beam that a drilling machine may slide, and e.g. be in the order of 0-10 metres.

In order to obtain a 3D-representation of the tunnel alignment, e.g. a representation of the desired tunnel cross section, in the following denoted tunnel contour, or tunnel profile, may be defined for each tunnel line point, e.g. in a plane perpendicular to the tunnel line TL. The tunnel contours of different tunnel line points may be defined in a same plane, but may also be defined in different non-parallel planes. An example of a tunnel contour 101 is disclosed in fig. 1 B, exemplifying a tunnel contour 101 of tunnel line point TLn, and which also indicates the location of the associated tunnel line point TLn in relation to the tunnel contour 101. For simplicity, the tunnel line point TLn is shown as being located essentially in the centre of the tunnel contour 101 of fig 1 B, but it may be arbitrarily located on, or principally anywhere on a plane of, the tunnel contour 101 for as long as the relation between tunnel line point and tunnel contour is defined. Positioning of the desired tunnel contour to encompass the associated tunnel line point may be advantageous e.g. from a navigation point of view during actual excavation.

The interconnected tunnel line points together with the associated tunnel contours, which may vary in shape from one tunnel line point to another can be used to form a 3D-volume through interpolation representing the tunnel and which is being defined in a coordinate system to allow excavation at a desired location. Consequently, the tunnel is represented by tunnel contours distributed along the tunnel line TL representing the desired extension of the cavity to be excavated. In case the tunnel contours differ from one tunnel line point to another, e.g. interpolation can be utilised in a straight-forward manner to obtain a tunnel cross-section also at any point between the defined tunnel line points. In case the tunnel contours are defined in a same plane 2D-interpolation may be utilised, while otherwise 3D-interpolation may be utilised to determine an intermediate tunnel contour in any desired plane.

Tunnel/cavity excavation of this kind often involves generation of a drill plan, in the following denoted drilling pattern, for drilling of a set, or round, of drill holes in a rock face for subsequent blasting. The drilling pattern defines the holes to be drilled, e.g. in the coordinate system of the tunnel, and may define position, length and direction for each hole. Holes having different diameters may also be drilled, and hence a hole diameter may be defined by the drilling pattern as well. Following drilling of a round, the drilled holes are charged with explosive material that is detonated following drilling and charging of the holes of the drilling pattern.

After the explosion, broken rock is taken away and following scaling, if required, i.e. clearing and loosening of cracked and/or partly loose rock resulting from the blasting, a new round is drilled and blasted to progress the excavation of the tunnel. This is then repeated until the complete volume of the desired tunnel/cavity has been excavated. When generating a drilling pattern of a round to be drilled the object is in general to design the drilling pattern such that the cavity formed by the blasting following the drilling results in a cavity having a spatial extension that at least clears the rock encompassed by the 3D-representation of the desired cavity, such as the cavity defined by an interpolation of the tunnel line points and associated contours. In reality surplus rock is oftentimes excavated in addition to the breaking of rock forming the desired cavity. This is due to a difficulty in breaking rock precisely according to desired cavity boundaries. It is, however, usually a requirement that the desired cavity is also excavated in full, i.e. the complete cross section of any given point of the tunnel being cleared from rock, and in order to ensure that at least this is accomplished surplus rock is oftentimes broken to ensure that under-breaking does not take place. The drilling pattern may be designed in an attempt to reduce the breakage of surplus rock as much as possible while still ensuring that at least the desired cavity is excavated.

Fig. 2 illustrates an exemplary movable rock drilling rig 201 that may be utilised e.g. in tunnel excavation. The rock drilling rig 201 is an underground drilling rig and is shown in position for drilling a round of holes in a rock face 202 during tunnel excavation, e.g. along the tunnel line TL of fig. 1 A.

As can be seen in fig. 2, the rock drilling rig 201 according to the disclosed example is provided with three booms 203-205, each of which is carrying a drilling machine 206-208 via feed beams 209-211. Accordingly, the disclosed rock drilling rig 201 may drill up to three holes at a time. Drilling rigs of the disclosed kind are known per se. The drilling machines 206-208 are, in this example, hydraulically driven and power supplied from one or more hydraulic pumps 212, which in turn are driven by one or more electric motors and/or combustion engines 213, also in a manner known per se. The drilling process may be controlled by an operator from a cabin 215.

The drilling rig 201 further comprises a control system comprising at least one control unit 214, which controls various of the functions of the drilling rig 201 , e.g. by suitable control of various actuators/motors/pumps etc. Drilling rigs of the disclosed kind may comprise more than one control unit, where each control unit, respectively, can be arranged to be responsible for different functions of the drilling rig.

The drilling rig 201 is arranged to be repositioned as excavation progresses and comprises, according to the present example, wheels 216, 217 for allowing drilling rig movability. Crawler drives or other suitable means may alternatively be used to allow manoeuvring of the drilling rig 201.

Fig. 2 hence discloses a drilling rig that following a previous blast and clearing of broken rock has been moved forward in the excavating direction, i.e. along the tunnel line TL, towards the rock face 202 resulting from the previous blast and the drilling rig 201 has been positioned for drilling the subsequent round for blasting of the next section of the tunnel/cavity to be excavated. In order to correctly excavate rock according to the predetermined tunnel alignment, the exact position of the rock drilling rig 201 in the prevailing coordinate system must be determined. This can be accomplished in various ways and, for example, by aligning one of the feed beams, e.g. feed beam 211 to a laser beam of a theodolite (not shown), where the position of the theodolite in turn has been established using fixed points.

The drilling rig in 201 general comprises a local rig coordinate system, and through the use of the drilling rig coordinate system the position of the drilling rig can be determined using the location of the feed beam in the drilling rig coordinate system and the location of the feed beam as determined in the coordinate system of the tunnel. In addition to the feed beam being aligned with a laser beam of a theodolite, the position of the feed beam along the laser beam must also be determined. This can be performed e.g. by straight-forward measurement or in any other way.

For example, the length of the tunnel that so far has been excavated from the beginning of the excavation, i.e. the drilled and blasted length of the tunnel, may e.g. be marked on the tunnel wall to facilitate positioning of the drilling rig. As is realized, any other suitable method of positioning the drilling rig in the coordinate system of the tunnel to be drilled may be utilized. According to embodiments of the invention, the drilling rig is provided with fixed points, which may be used to position the drilling rig using e.g. a theodolite, and where the rig fixed points are also defined in the coordinate system of the drilling rig, so that thereby e.g. the position of a feed beam may be determined in the coordinate system of the tunnel.

As before mentioned, prior to drilling of the rock face 202 commences, a drilling pattern is generated, and fig. 3 illustrates a highly schematic flowchart for generating a drilling pattern to be drilled prior to blasting the current rock face 202. The positions of the holes to be drilled on the rock face are schematically illustrated by “x” markings, where these positions are determined by the drilling pattern. The drilling pattern to be used is oftentimes determined prior to the excavation of a tunnel commences e.g. in a planning centre, where the holes are planned such that the subsequent blasting as close as possible corresponds to the desired cavity to be excavated. The generation of the drilling pattern that is optimal from an excavation point of view, e.g. with regard to surplus rock being broken, may be difficult, in particular when excavation is in progress and the excavation has progressed to a position along the tunnel line that does not correspond to a position for which drilling is planned to be performed on the planning stage. According to the invention, it is provided a method for generating a drilling pattern that takes further factors into account when generating the drilling pattern in an attempt to reduce the amount of surplus rock being broken during the excavation.

This is accomplished by means of a method 300 according to fig. 3, which starts in step 301 by determining whether a drilling pattern is to be generated. This may be initiated e.g. by an operator of the drilling rig 201 , e.g. by suitable input to the drilling rig control system, or by any other suitable means. The method continues to step 302 when a drilling pattern is to be generated while otherwise the method remains in step 301. In step 302 a representation of the location of the rock face to be drilled is determined, e.g. by positioning the drilling rig according to the above using the coordinate system of the drilling rig in combination with the position of the drilling rig in the coordinate system of the tunnel, where the representation of the rock face can be expressed in the coordinates of the coordinate system being used for excavation of the tunnel. The rock face is often represented by a navigation plane, which can be arranged to be located in any conventional manner with regard to the rock face, e.g. as discussed below with reference to figs. 5-12.

When the position of the rock face 202 in the coordinate system of the tunnel has been determined, a desired contour/profile of the tunnel section to be drilled and longitudinal alignment may also be determined, e.g. through the use of interpolation using the tunnel contours of the tunnel line point or points closest to the rock face 202.

In step 303, the drilling pattern is generated on the basis of the predetermined contour and alignment of the tunnel section about to be drilled. The drilling pattern may basically be generated according to any of the various known technologies for generating a drilling pattern, but according to embodiments of the invention, in addition, further aspects are taken into account when generating the drilling pattern. In general when generating a drilling pattern, holes to be drilled close to the periphery of the rock face are subject to limitations regarding possible hole direction. This is due to the inherent diameter/size of the drilling machine/feed beam. That is, it is not possible to drill precisely along a contour outline but drilling will have to be performed slightly outwards in relation to the desired direction to make room for drilling machine/feed beam when drilling the next round of holes following blasting of the current round. This is known per se, and the general principle is illustrated in fig. 4, where in which a desired width of a tunnel to be drilled is indicated with a, in which the actual drilling is represented as a saw tooth pattern 401 , in which the distance b is essentially governed by the dimensions of the drilling machine/feed beam, and where the distance b ensures that the width of the tunnel can be maintained at the subsequent round. That is, if the distance b is made smaller in one round, this may make drilling difficult in a following round, so that the drilling e.g. will be directed more outwards due to space limitations. Fig. 4 merely illustrates a general principle, and the outward angulation c may be determined in any suitable manner, in general in an attempt to limit over-breakage of rock, where the outward angulation c may vary from one round to another.

However, according to embodiments of the invention, other parameters than the limitations of fig. 4 are taken into account. Therefore, when generating the drilling pattern in step 303 in fig. 3, limitations imposed by the already excavated portion of the tunnel regarding manoeuvrability of the rear end 209B, 21 OB, 211 B of the feed beam 209-21 1 is also taken into account when generating the drilling pattern. The tunnel walls of the already excavated portion of the tunnel will impose restrictions on possible manoeuvring of the feed beam(s) of the drilling rig so that holes that would be desired to drill from an excavation point of view e.g. to reduce the amount of surplus rock being excavated may not in reality be possible to drill due to feed beam space limitations, which may render a required manoeuvring of the feed beam in order to drill the holes according to the determined drilling pattern impossible. This may be the case, for example, when the cavity to be drilled is narrowing, and/or when cavity is not following a straight line.

When generating the drilling pattern, a hole desired to be drilled may be checked, step 304 regarding manoeuvrability as soon as a hole has been determined to be drilled, or following the generation of the complete drilling pattern, where holes being found to be unsuitable from a drillability perspective may be re-determined. This may result e.g. in holes being replaced by holes having another direction and possibly a different hole length. An iteration may be performed until all holes are considered drillable in step 304, in which case the method is ended in step 305. The rock face may then be drilled according to the determined drilling pattern.

Hence, according to embodiments of the invention, a drilling pattern may be generated that will also be drillable, and that may not be subject to manoeuvring difficulties due to surrounding rock being unaccounted for. In this way it can be ensured that rock is excavated to an extent sufficient to provide the desired cavity while simultaneously breaking of surplus rock may be reduced by creating a drilling pattern that take the actual conditions prevailing at the location of the rock face regarding manoeuvrability of the feed beam into account to thereby create a drilling pattern that may result in less surplus rock being excavated than otherwise might be the case. According to embodiments of the invention, the disclosed method may be most beneficial in sections where the contour is changing, in particular narrowing and/or the tunnel is curving or the curvature of the tunnel is changing.

According to embodiments of the invention, the representation of the tunnel in the tunnel coordinate system, e.g. as determined by the tunnel line TL and associated contours according to the above, be used to determine possible manoeuvrability of the feed beam and thereby drillability of a hole when generating the drilling pattern. That is, the cavity that is assumed to have been excavated up to the face to be drilled may be utilised, where a 3D-representation of the assumed cavity may be obtained, for example, using interpolation according to above.

According to embodiments of the invention, a contour of the already excavated portion of the tunnel at a distance from the face to be drilled substantially corresponding to the length of the feed beam may be used to determine limitations regarding the manoeuvrability of the end of the feed beam facing away from the drilling direction when determining drillability of a hole.

According to embodiments of the invention, the actual rock walls are instead used to determine drillability of the holes of the drilling pattern. This may be accomplished, for example, by scanning the rock walls as the excavation progress. Since there oftentimes is an over-breakage of rock, this may render further feed beam manoeuvring possibilities, so that holes that may not be considered drillable using the theoretical extension of the cavity may in reality still be drillable.

Further, embodiments of the invention relates to particular methods for generating the drilling pattern that take limitations regarding manoeuvrability of the feed beam into account.

In the following, therefore, an inventive method 500 of fig. 5 according to embodiments of the invention for generating a drilling pattern will be exemplified. The method will be exemplified with further reference to figures 6-12.

In FIG. 6 a tunnel line TL is illustrated which is similar to the tunnel line of fig. 1 A, but where in addition the desired outline 601 of the tunnel as seen from above is also illustrated. In addition, the actual rock walls 602 of the already excavated portion of the tunnel are shown, including the rock face 603 about to be drilled as the excavation progress. As has been discussed above, the tunnel line points are defined in the coordinate system being used in the excavation, and in the present example drilling has reached a point between TLn and TLn+1. Even if, prior to the excavation of the tunnel commences, it may be an intention to drill consecutive rounds at consecutive tunnel line points, drilling may not progress precisely according to pre-planned drilling patterns, where each round of drilling and blasting may be expected to reach the next tunnel line point of the tunnel line TL. For example, the blasting may not break the full length of a hole, and/or a larger portion of rock may be broken, e.g. due to more porous rock. According to embodiments of the invention, however, the drilling pattern for the next round is established only once the location of the rock face to be drilled has been determined, and is independent from the current progress in relation to the tunnel line points.

The exemplified method in fig. 5 starts in step 501 , where, similar to the method of fig. 3, it is determined whether a drilling pattern is to be determined. When this is the case, the method continues to step 502 where a face contour FC of the current rock face to be drilled is determined. The face contour FC is determined for a plane, here denoted navigation plane NP as is commonly the case, from which hole length, direction etc. of the holes to be drilled is determined. As can be seen from fig. 6, the resulting rock face 603 from the preceding blast is uneven, and may vary considerably. The navigation plane NP may be determined such that it substantially or completely clears the rock face 603 to be drilled, but the navigation plane NP may also be arranged to partially or fully intersect the rock face 603 to be drilled.

The navigation plane NP may be defined in various ways, and according to the present example, the navigation plane NP is defined such that it is perpendicular to a line, dashed line 605, representing an intended drilling direction of the round to be drilled. The intended drilling direction may, as in the present example, differ from the direction of the tunnel line TL at the point where the tunnel line TL is intersected by the navigation plane NP. For example, the direction of drilling may be determined by a line 605 that intersect the tunnel line TL at the point where the tunnel line TL is intersected by the navigation plane NP, and where the line 605 also intersects the tunnel line TL, point 604, at some suitable distance from the navigation plane NP. The distance from the navigation plane NP to point 604 may correspond to, or substantially correspond to, the longest hole length to be drilled in the round for which the drilling pattern is generated. The distance from the navigation plane NP to the point 604 may also be any other suitable distance, greater or smaller than the longest hole length to be drilled in the round. For example, the distance may be set or changed from a pre-set value e.g. by an operator in case it is desired to change the drilling direction, and in which case the navigation plane may be automatically adjusted to be e.g. perpendicular to the drilling direction. In the present example the navigation plane NP is hence determined such that line 605 is normal to the navigation plane NP. The navigation plane NP is hence defined independently from the general appearance of the rock face 603 to be drilled, and e.g. need not be parallel to this rock face 603, but may be angled considerably in relation to the actual rock face.

The navigation plane NP may also be defined independently from a drilling direction, and may essentially have any suitable angle in relation to e.g. the tunnel line TL and/or drilling direction 605 and/or rock face. There exist various methods in the art for determining a navigation plane NP, and any such method may be utilised. For example, the navigation plane NP can be arranged to be determined e.g. by an operator of the drilling rig and/or other person involved in the generation of drilling patterns. Further, an intended drilling direction may be defined according to any suitable criteria and may have any suitable direction and hence need not be defined according to the example using tunnel line points described herein.

The face contour FC is determined in the navigation plane NP, where the face contour FC can be determined by 2D or 3D interpolation as explained above using the tunnel contours of TLn and TLn+1 , depending on whether these tunnel contours are in a same plane or not, to obtain the face contour in the navigation plane NP. The tunnel line contours of adjacent tunnel line points may differ in shape from one tunnel line point to another, e.g. if the tunnel is narrowing or otherwise changing shape, and may be defined in different planes, e.g. by the curvature changing such as in the present example, where tunnel line contours of tunnel line points TLn and TLn+1 are also in different planes with respect to the navigation plane NP. The navigation plane NP hence need not, and according to the present example is not, be perpendicular to the tunnel line at the point where this is crossed, and the face contour FC will therefore differ from the tunnel line contour even if the tunnel contours of adjacent tunnel line points TLn and TLn+1 are the same. The exemplified method is perhaps most advantageous when conditions for generating the drilling pattern differ from one round to another, in particular when the tunnel is narrowing and/or the tunnel is curving or the curvature of the tunnel is changing.

The method then continues to step 503 in which, in a similar manner to the above, a bottom contour BCO is determined. The bottom contour BCO is determined in a bottom plane BP, which is a plane at a distance from the face contour FC. The bottom plane may be defined to be located at a distance from the face contour FC, e.g. defined by line 605 above, and hence at a distance e.g. corresponding or substantially corresponding to the longest length of the holes to be drilled in the round for which the drilling plan is generated. The bottom plane BP may also be arranged to be located at any other, greater or smaller, distance from the face contour FC. The location of the bottom plane BP may also be arranged to be adjusted by an operator of the drilling rig, e.g. by changing pre-determined distance between face contour and bottom plane in case this is desired, e.g. to extend or reduce the distance between the face contour/navigation plane and the bottom plane BP. The distance between the face contour and bottom plane may hence exceed the longest hole length to be drilled. Further, in case the planes are angled with respect to each other, the distance between the planes will vary in dependence on where on the planes measurement is made, and hence the distance may be both greater and smaller than the longest hole length to be drilled even if e.g. the distance along the tunnel line equals the longest hole length to be drilled. The bottom plane BP, and thereby bottom contour BCO may be arranged to be perpendicular to the tunnel line TL where this is intersected, i.e. at point 604 in the present example. The bottom plane BP may alternatively be arranged to be perpendicular to the line 605, and hence be parallel to the navigation plane NP. The bottom plane may also be defined in any other suitable manner. The bottom contour BCO may be determined using 2D or 3D interpolation, in this case using tunnel line points TLn+1 , TLn+2.

In step 504 a further contour, a limiting contour LC, is established. The limiting contour LC is also interpolated using adjacent tunnel line contours, TLn-2, TLn-1 , in a manner similar to the above at a distance from the face contour FC, and in a direction from the face contour FC opposite the drilling direction. The distance between the face contour FC and the limiting contour LC may e.g. be selected to equal the length of the feed beam of the drilling rig. The limiting contour LC is used to take surrounding rock of the already excavated portion of the tunnel into account according to the above to determine drillability of the holes when determining the drilling pattern so that the manoeuvrability of the feed beam is taken into account.

The limiting contour LC may be interpolated using tunnel line contours as above, but if a scanned representation of the actual rock wall of the already drilled portion of the tunnel is available this can be used instead to increase accuracy when determining if holes are drillable or not. Furthermore, the limiting contour LC may be selected such that it’s normal vector coincides with the direction of navigation and hence the limiting contour LC is parallel to the face contour FC.

According to the present exemplary method for generating a drilling pattern at the current location of the drill rig, a drilling pattern encompassing the face contour FC to be drilled is formed by generating separate drilling patterns for different portions of the face contour FC. Therefore, in step 505 a first maximum contour MC0 is generated. This maximum contour MC0 represents the maximum possible portion of the face contour FC where it is possible to drill the holes having the maximum length being drilled during the excavation of the tunnel, while ensuring manoeuvrability of the feed beam. The maximum contour MC0 is arranged to be in the navigation plane NP, i.e. the same plane as the face contour FC. The boundaries of the maximum contour MC0 is limited by the periphery of the face contour FC, since this is the maximum surface to be drilled, but MC0 is also delimited by a 3D-interpolation using the limiting contour LC and the bottom contour BCO in the plane of the face contour FC. This is illustrated in FIG. 7 by dashed interpolation lines 701 and 702. The resulting contour MC0, delimited also by the face contour FC, is shown as the hashed area of fig. 8, which hence shows the face contour FC and the determined MCO. The area MCO, consequently, represents the portion of the face contour FC that may be drilled with full-length holes when drilling the next round. The area resulting from the interpolation that is located outside the face contour FC, i.e. the hashed area 801 , is disregarded since this area is not to be drilled.

When the maximum contour MCO has been determined according to the above, a drilling pattern is generated, step 506, for the maximum contour MCO, which hence constitutes a drilling pattern of holes to be drilled from face contour FC to the bottom contour BCO. The drilling pattern for the maximum contour MCO may alternatively not be generated until all contours according to the below have been established. That is, the various contours are first established, whereafter the drilling pattern is generated for the various portions of the face contour. The drilling pattern of the maximum contour MCO can be generated according to any suitable method for generating a drilling pattern for drilling a contour towards a bottom contour, where various methods are known in the art. The drilling pattern of maximum contour MCO will not, since this contour does not encompass the full face contour FC, represent the total volume that is to be drilled and blasted during the round to be drilled.

Additional drill holes must be added in order to drill the full volume. Therefore, the remaining portion of the face contour, i.e. the non-hashed portion of fig. 8, shown as hashed in fig. 9 and denoted DC, is still to be drilled, but full-length holes may not be utilised due to the manoeuvrability limitations of the feed beam, but holes having a length being less than the maximum length of the holes of the round to be drilled may be used for this portion of the face contour.

In step 507, therefore, the difference surface, contour DC, constituting the difference between the face contour FC and the maximum contour MCO is determined. With regard to this surface, a drilling pattern is to be generated where holes are drilled to a shorter length than holes being drilled when drilling the generated drilling pattern of the maximum contour MCO.

It is therefore determined a number of rows of holes to be drilled on the difference contour DC. This can be established, for example using rules regarding distance between holes to be used when generating drilling patterns, where this distance can be dependent e.g. on the properties of the rock to be drilled, diameter of holes to be drilled, length of the section of rock that is about to be excavated in the current round etc., as is known per se. This determination regarding the holes, however, is oftentimes already performed, and is therefore not part of the invention. Hence, when e.g. the applicable hole distance is established, a number of rows of holes to be drilled in the difference contour DC may also be determined.

The determined number of rows of holes to be drilled, and/or alternatively the width of the difference contour DC, is then used to establish a number n intermediate bottom contours BC1 ...BCn, step 507, to be used between the face contour FC and the original bottom contour BCO. For example, one bottom contour can be generated for each, e.g. vertical or horizontal row of holes to be drilled in the difference contour DC. The intermediate bottom contours BC1 ...BCn can be generated in the same manner as BCO above, i.e. through interpolation using the tunnel contours of the adjacent tunnel line points. With regard to the location of the bottom contours BC1 ...BCn, these can be arranged to be evenly spaced between the face contour FC and the bottom contour BCO. That is, for example, if only one additional drilling pattern is to be generated, the additional bottom contour BC1 can be arranged to be positioned at half the distance from the face contour FC to the bottom contour BCO. The distances to the additional bottom contours/planes may also be determined in any other suitable manner, e.g. in dependence of the curvature of the cavity to be drilled.

According to the present example, two additional bottom contours BC1 , BC2 are generated, which are evenly spaced between the face contour FC and the bottom contour BCO. This is illustrated in fig. 10, where the two intermediate planes BC1 , BC2 are shown. Other distributions than even distances between contours may also be utilised. A drilling pattern may then be generated for each additional bottom contour BC1 ...BCn, step 508, where the additional drilling patterns can be generated using the above described principle, by interpolating, respectively, the additional bottom contours BC1 ...BC2 and the limiting contour LC in the plane of the face contour, and further delimit by the face contour FC. This is illustrated by the lines 1001 , 1002 used in the interpolation in fig. 10, and the portion to be drilled to a hole depth delimited by BC1 is schematically indicated as MC1 portion of DC in fig 9, and the portion to be drilled to a hole depth delimited by BC2 is schematically indicated as MC2 portion of DC in fig 9. Portions of the face contour FC for which drilling patterns have already been generated, e.g. MCO, are disregarded. As was mentioned above, the drilling pattern for MCO may be generated after the portions MC1 , MC2 have been determined. Hence, when generating a drilling pattern for BC1 , this will, according to the present example, render one or more further row of holes to be drilled, essentially having a length corresponding to the distance between the face contour FC and the intermediate bottom contour BC1. Again, holes regarding portions of the face contour FC for which a drilling pattern has already been generated are disregarded. Furthermore, holes being too close to already planned holes, e.g. for the maximum contour MCO may also be disregarded, since the already planned holes in general will be holes of a longer length. Alternatively, such holes may be omitted from the drilling pattern of MCO instead.

When the drilling pattern for the first intermediate bottom contour BC1 has been generated, a drilling pattern is generated for the second intermediate bottom contour BC2 in a similar manner, which in this example will render one or more further row of holes to be drilled, essentially having a length corresponding to the distance between the face contour FC and the second intermediate bottom contour BC2, i.e. holes having a yet shorter length. In addition to holes regarding portions of the face contour FC for which a drilling pattern has already been generated with respect to the bottom contour BCO, holes of the drilling pattern for the first intermediate bottom contour BC1 are also disregarded, and also holes being too close to already planned holes as discussed above.

When drilling patterns have been generated for the bottom contour BC and the intermediate contours BC1 , BC2, consequently, an aggregate drilling pattern covering the full face contour FC have been generated, and fig. 11 schematically illustrates the holes to be drilled by solid lines extending from the face contour FC to the bottom contours, respectively. The aggregate drilling pattern may then be drilled one at a time or be treated as a single aggregated drilling pattern, step 509, where holes may be drilled in any order and not just one drilling pattern at a time. The method is then ended in step 510.

The drilling patterns regarding the different bottom contours may also be generated in any other order, still for the same areas, but shorter holes may be maintained instead of longer holes in the border areas should this be considered advantageous, e.g. to reduce surplus rock. Also, the different portions MCO, MC1 etc. may be determined prior to the actual drilling patterns are being determined.

Furthermore, according to embodiments of the invention, the areas of the face contour FC not covered by the maximum contour MCO may be enlarged, i.e. the area of MCO may be reduced. This may be carried out e.g. in order to make room for one or more further rows of holes in case the difference contour is determined to be too small, e.g. being too narrow. Such parameters may be pre-set in the control system.

Enlargement of the difference area may be accomplished by reducing the size of the maximum contour MCO. For example, the limiting contour LC can be projected to the face contour FC in the navigation plane, instead of utilising interpolation, thereby further limiting the size of the maximum contour MCO. This is exemplified in fig. 7 by dotted line 710, which hence renders the maximum contour MCO smaller, thereby increasing the area to be drilled using shorter hole lengths.

The projection may be used in combination with interpolation according to the above, but projection may also be utilised instead of the interpolation. That is, for example, only the limiting contour LC or a bottom contour BCO may be used in the establishment of the maximum contour MCO /difference contour. Consequently, according to embodiments of the invention, only the bottom contour BCO or Limiting contour LC is determined in the method of fig. 5.

According to the above example, projection of the bottom contour BCO onto the face contour FC may not impose any substantial differences. Flowever, according to other situations, such as e.g. situations of the kind shown in fig. 12, projection of the bottom contour BCO onto the face contour FC may be suitable to use.

Fig. 12 illustrates a situation where the tunnel is narrowing, i.e. the tunnel/cavity is transitioning from a wider section to a narrower section. The line 1201 exemplifies interpolation according to the above, which results in a maximum contour MCO having a width corresponding to line 1203. According to the example disclosed in fig.

12, the maximum contour MCO can be reduced by projecting the bottom contour BCO onto face contour FC instead of utilising interpolation.

This is illustrated by line 1202, which represents projection of the bottom contour BCO onto the face contour FC and results in a maximum contour MCO having the smaller width indicated by line 1204 in the figure. This, in turn, increases the part of the face contour FC for which holes having a reduced length are to be drilled, the increase of the difference contour, i.e. reduction of the maximum contour MCO, being indicated by line 1205.

Finally, for the sake of simplicity, the bottom contours BCO, BC1 , BC2 have been illustrated as at least essentially planar surfaces. This need not be the case, but any of or all of the bottom contours may take any desired shape.

Furthermore, the method for generating a drilling pattern has been described above as being carried out by a drilling rig that is present at a location where a rock face is about to be drilled. According to embodiments of the invention, the generation of the drilling pattern may be carried out by a computer e.g. in a planning centre, where e.g. a drilling pattern may be generated for any location of the cavity to be drilled, so that personnel e.g. may evaluate the generated the drilling pattern, and adjust input parameters to be used in the generation of the drilling pattern.

Claims

1. A method for generating a drilling pattern for excavating a cavity in rock, the drilling pattern determining holes (x) to be drilled in a face (603) of the rock, the determination of the holes (x) to be drilled being a determination of location, direction and length of the holes (x) to be drilled, the holes being arranged to be drilled by a drilling rig (201) comprising at least one feed beam (209-211) carrying a drilling machine (206-208), the at least one feed beam (209-211 ) having a first end (209A;210A;211 A) arranged to, during drilling, face the rock to be drilled and a second end (209B;210B;211 B) being opposite to said first end, the method being characterised in:

- generating a drilling pattern comprising holes (x) having a drillability, the drillability of said holes (x) being determined when generating said drilling pattern by ensuring a manoeuvrability of said second end (209B;210B;211 B) of said at least one feed beam (209-211) in relation to surrounding rock.

2. Method according to claim 1 , further including:

- ensuring a manoeuvrability of said second end (209B;210B;211 B) of said at least one feed beam (209-211) in relation to surrounding rock utilising a representation of the rock surrounding said second end (209B;210B;211 B).

3. Method according to claim 1 or 2, further including:

- ensuring a manoeuvrability of said second end (209B;210B;211 B) of said at least one feed beam (209-211) in relation to surrounding rock utilising a representation of the cavity in a coordinate system of the cavity.

4. Method according to any one of claims 1 -3, further including:

- ensuring a manoeuvrability of said second end (209B;210B;211 B) of said at least one feed beam (209-211) in relation to surrounding rock utilising a representation, such as generated by one or more scanners, of actual rock walls resulting from blasting of a previous round of drilling.

5. Method according to any one of claims 1 -4, further including:

- ensuring a manoeuvrability of said second end (209B;210B;211 B) of said at least one feed beam (209-211) in relation to surrounding rock utilising a representation of a cross section of the cavity at a distance from a

representation of the face to be drilled substantially corresponding to the length of the feed beam.

6. Method according to any one of the claims 1 -5, further including:

- determining the drillability of said holes (x) when the cross section of said cavity is narrowing in the direction of excavation , and/or a curvature of the cavity is changing.

7. Method according to any one of the claims 1 -6, further including:

- determining a face contour (FC) representing the rock face to be drilled and constituting a cross section of the cavity in a plane (NP) representing the rock face to be drilled.

8. Method according to claim 7, further including:

- determining said drilling pattern as a first drilling pattern for a first part (MCO) of the face contour (FC), and at least one second drilling pattern for at least one second part (MC1 , MC2), different from said first part (MCO), of the face contour (FC), a maximum hole length of holes of the first drilling pattern being longer than a maximum hole length of holes of the second drilling pattern.

9. Method according to claim 8, further including:

- determining a first contour (LC), said first contour (LC) being a representation of the cross section of the cavity at a distance from the face contour (FC) substantially corresponding to the length of the feed beam,

- determining a second contour (BCO), said second contour (BCO) being representation of a cross section of the cavity at a distance from the face contour (FC) in the drilling direction, and

- determining said first part (MCO) and/or said second part (MC1 , MC2) of the rock face to be drilled utilising said first (LC) and second (BCO) contour.

10. Method according to claim 8 or 9, wherein said second contour (BCO) is a representation of a cross section of the cavity at a distance from the face contour (FC) substantially corresponding to the maximum length of the holes to be drilled, and

11. Method according to claim 9 or 10, further including:

- determining said first part (MCO) and/or said second part (MC1 , MC2) of the face contour (FC) utilising interpolation between said first contour (LC) and said second contour (BCO), the first part (MCO) and/or said second part (MC1 , MC2) being delimited also by the face contour (FC).

12. Method according to any one of claims 9-11 , further including:

- determining said first part (MCO) and/or said second part (MC1 , MC2) of the face contour (FC) utilising projection of said first contour (LC) and/or said second contour (BCO) onto the face contour (FC).

13. Method according to any one of the claims 8-12, further including:

- on the basis of the remaining part (DC) of said face contour (FC) not being encompassed by said first part (MCO), determining at least one intermediate contour (BC1 , BC2) between said face contour (FC) and said second contour (BCO), each of said at least one intermediate contour (BC1 , BC2) representing a cross section of the cavity at different distances from the face contour (FC), wherein said at least one intermediate contour (BC1 , BC2) is used when generating a drilling pattern of said remaining part (DC), and wherein a drilling pattern is generated for different parts of said face contour (FC) for each of said intermediate contours (BC1 , BC2) utilising said intermediate contour, respectively, and said first contour (LC).

14. Method according to any one of the claims 8-13, further including:

- when holes of drilling patterns for different parts of said face contour (FC) are located less than a first distance from each other, omit holes of at least one of said drilling patterns.

15. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of the preceding claims.

16. Computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to any one of the claims 1-15.

17. System for generating a drilling pattern for excavating a cavity in rock, the drilling pattern determining holes (x) to be drilled in a face (603) of the rock, the determination of the holes (x) to be drilled being a determination of location, direction and length of the holes (x) to be drilled, the holes being arranged to be drilled by a drilling rig (201 ) comprising at least one feed beam (209-211) carrying a drilling machine (206-208), the at least one feed beam (209-211 ) having a first end (209A;210A;211 A) arranged to, during drilling, face the rock to be drilled and a second end (209B;210B;211 B) being opposite to said first end, the system being characterised in:

- means for generating a drilling pattern comprising holes (x) having a drillability, and

- means for determining the drillability of said holes (x) when generating said drilling pattern by ensuring a manoeuvrability of said second end

(209B;210B;211 B) of said at least one feed beam (209-211 ) in relation to surrounding rock.

18. Rock drilling rig (201) comprising a system according to claim 17.