Patent Description:
Traditional drilling and excavation methods utilize drills to form holes in one or more layers of material to be penetrated. For example, conventional mining techniques to form a tunnel or shaft in rock or a similar material may include combinations of drilling and blasting operations (e.g., use of explosives). These operations may produce broken rock and other debris, and hauling operations may be used to transport the broken rock and other debris away from a workface. These processes may account for over <NUM>% of the time utilized in a mining operation, which may slow the advancement of a mining shaft or tunnel. For example, using conventional mining techniques, a tunnel may only be advanced by a distance of <NUM>-<NUM> feet (about <NUM>-<NUM> meters) per round (e.g., one cycle of tunneling or blasting followed by one cycle of debris removal), which may result in an advancement of a shaft or tunnel by a distance of less than <NUM> feet (about <NUM> meters) per day.

<CIT> discloses a drill-and-blast excavating apparatus and method. <CIT> discloses a controlled fracture method and apparatus for breaking hard compact rock and concrete materials. <CIT> discloses tround terra-drill processes and apparatus. <CIT> discloses a ram accelerator system with an endcap which may be used to form one or more holes in geologic or other material.

As used throughout this application, the word "may" is used in a permissive sense (i.e., meaning having the potential to) rather than the mandatory sense (i.e., meaning must). Similarly, the words "include", "including", and "includes" mean "including, but not limited to".

Described in this disclosure are techniques that may enable generally continuous mining, tunneling, and boring operations, which may improve efficiency over conventional techniques. To weaken the rock or other material located at a workface, such as the end of a shaft or tunnel to be extended, projectiles may be accelerated into the workface. In some implementations, a ram accelerator assembly may use pressurized gas to accelerate the projectiles using a ram effect caused by interaction between exterior features of the projectile and interior features of a tube or other conduit of the ram accelerator assembly. In some implementations, a projectile may be accelerated using combustion of materials, such as low-cost chemical energy generated by the combustion of diesel or natural gas. Additionally, in some implementations, projectiles may be formed from low-cost materials, such as concrete. In some implementations, the materials, the geometry, or both the materials and the geometry of the projectiles may be customized to control the depth by which a tunnel is extended or to affect the shape of the tunnel. For example, a pointed or wedge-shaped projectile may penetrate more deeply and easily into certain types of materials. Additionally, the types and quantities of accelerants used to apply a force to the projectiles may also be modified to customize the characteristics of the impact with the rock face. For example, accelerating a projectile to a ram velocity using a pressurized gas may affect the manner in which the projectile interacts with the workface and the shape of a crater that is formed, when compared to an impact by a projectile having a lower velocity.

The impact of an accelerated projectile with a rock face or other type of workface may displace or weaken the material of the workface, which may facilitate extending a tunnel or shaft through the material more rapidly and more safely. After impacting a workface with one or more projectiles, a boring or reaming tool may be brought into contact with the workface. The boring or reaming tool may more easily and quickly penetrate through the weakened material, with less wear on the cutting surfaces of the tool. Additionally, in some implementations, the disclosed mining, tunneling, and boring operations may be performed while decreasing or eliminating conventional use of explosives in on-site operations, which may decrease cost and increase safety associated with the operations. For example, use of projectile impacts to weaken a workface may cause the use of explosives to be unnecessary in some cases. In some cases, extending a tunnel using accelerated projectiles may be performed from <NUM> to <NUM> times more rapidly than conventional methods, at up to <NUM>% lower cost. For example, use of accelerated projectiles to impact a workface may enable faster boring than conventional methods since the power provided by the impact of the projectiles is equal to <NUM>*D*V^<NUM>, where D is the density of the projectile and V is the velocity of the projectile. For example, use of accelerated projectiles traveling at a speed of <NUM>-<NUM> meters per second may have a dynamic pressure that is <NUM> to <NUM> times the strength of the rock or other material impacted by the projectiles. Factors that affect the interaction between a projectile and a workface may include projectile velocity, projectile mass, and the ration of the density of the projectile to that of the workface.

In some implementations, the described operations may be performed more continuously than conventional techniques by performing operations to remove debris at least partially simultaneously with boring operations. For example, a ramp, conveyor system, or other device for collecting debris formed by projectile impacts and boring operations may remove debris to a trailer or other movable receptacle for collecting debris or other material. Continuing the example, a reaming or boring tool may be attached to a vehicle, rails, or other means of providing motion to the tool. A collection plate, ramp, conveyor system, or similar mechanism may be positioned on the same vehicle or assembly, such that debris created by the boring or tunneling operations may be collected and removed while the boring or tunneling operations are performed. In some implementations, one or a series of vehicles or other types of assemblies that are configured to be moved into and out from a tunnel that is being formed may be used to perform the operations described herein. For example, a ram accelerator assembly may move along rails, tracks, wheels, and so forth to be placed in a position to accelerate one or more projectiles into a workface. A boring tool may be positioned on a wheeled or tracked vehicle, or other type of movable assembly, to be brought into contact with the workface after one or more projectile impacts. A collection assembly for collecting and removing debris from the workface may be associated with the same vehicle or assembly as the boring tool, or a separate vehicle or assembly, and may be moved into a position to remove debris created by a boring or tunneling operation. In some implementations, the disclosed mining, tunneling, and boring operations may be performed remotely, such as through use of autonomous equipment or equipment that may be controlled remotely. For example, one or more computing devices located in a location remote from that of the equipment may be used to communicate with controllers associated with ram accelerator assemblies, boring assemblies, collection assemblies, and so forth to control the use of projectiles, boring tools, and the collection of debris. In some implementations, the described operation comprise accelerating a second projectile into contact with a second region of the geologic material, wherein the second projectile at least partially weakens the geologic material at the second region; contacting the second region of the geologic material with the cutting surface to displace at least a portion of the geologic material at the second region and form a second section of the shaft; and moving the cutting tool into the second section of the shaft.

Implementations described herein may be used in drilling, mining, tunneling, and boring operations, as well as open pit drilling, open pit bench mining, continuous underground and tunneling operations, continuous rock removal and categorization operations, and other types of operations. Use of low-cost industrial gasses as propellant material to accelerate projectiles, and low-cost material to form projectiles may enable efficient extension of tunnels and shafts at a lower cost than conventional techniques. Additionally, faster rates for advancing a tunnel or shaft at a lower cost may be achieved by increasing the velocity and mass of projectiles. The firing parameters for a ram accelerator assembly may be selected to optimize for stability, speed, cost, or other factors.

<FIG> depicts an implementation of a system <NUM> that may be used for generally continuous tunneling, boring, or mining operations. The system <NUM> may include a plurality of vehicles or other types of assemblies that may be moved relative to a workface, such as the end of a tunnel or shaft. In some implementations, each assembly may be moved separately from other assemblies. Additionally, in some implementations, each assembly and the operation thereof may be controlled remotely, such as through use of one or more computing devices located remote from a site where a tunneling, boring, or mining operation is performed. Computing devices may communicate with controllers that are associated with various components of the system <NUM>, such as to cause acceleration of projectiles into a workface, actuation of a cutting tool, collection of debris, and so forth.

A first assembly of the system <NUM> may include a ram accelerator assembly <NUM>. The ram accelerator assembly <NUM> may be used to accelerate projectiles into a workface, such as the end of a tunnel or shaft to be extended. The ram accelerator assembly <NUM> may include one or more chambers for containing projectiles and propellant materials. For example, a first chamber may include a combustible material, such as diesel fuel, natural gas, or other types of material that may be ignited to apply a force to a projectile within a second chamber. In other implementations, the propellant material may include one or more gas generating materials. In still other implementations, the propellant material may include one or more explosive materials. In some implementations, a system may include equipment for performing high pressure electrolysis to create hydrogen and oxygen for use accelerating projectiles, reducing or eliminating the need to supply a ram accelerator assembly <NUM> with a separate source of propellant material. In some cases, multiple types of propellant materials may be used in different portions of the ram accelerator assembly <NUM>, such as a combination of diesel and air in a first portion and a combination of diesel and natural gas in a second portion. Independent of the source or type of propellant material used, the propellant material may apply a force to one or more projectiles to accelerate the projectile(s) toward workface. In some implementations, interactions between the projectile, force from the propellant material, and features of a tube or other portion of the ram accelerator assembly <NUM>, may impart a ram effect to the projectile. For example, interior baffles or rails within a tube of the ram accelerator assembly <NUM>, in conjunction with the exterior features of a projectile, may enable pressurized gas to accelerate a projectile using a ram effect. In some implementations, the projectile may achieve a ram velocity prior to exiting the ram accelerator assembly <NUM> and contacting a workface. In other implementations, the ram accelerator assembly <NUM> may not necessarily impart a ram effect to a projectile or cause the projectile to achieve a ram velocity.

The projectiles may have any shape and dimensions and may be formed from any type of material. In some implementations, the projectiles may be formed from concrete. In some implementations, the projectiles may have a wedge or tapered shape to facilitate penetration into a workface.

In some implementations, the ram accelerator assembly <NUM> may be moved toward and away from a workface via one or more rails <NUM>, which may be engaged to the ram accelerator assembly <NUM> using one or more guides <NUM>. In other implementations, the ram accelerator assembly <NUM> may be moved toward or away from a workface using wheels, tracks, treads, and so forth. For example, a trailer or other type of vehicle may be used to transport the ram accelerator assembly <NUM> within a tunnel or shaft.

Interactions between a workface and projectiles that are accelerated using the ram accelerator assembly <NUM> may at least partially crack, weaken, break, or pulverize rock or other material at the workface. In some implementations, the ram accelerator assembly <NUM> may be selectively aimed or otherwise positioned to impact a particular portion of a workface. A reaming tool <NUM> may then be used to extend a hole created by a projectile, such as by removing material from and around the area of the workface affected by the impact. In some implementations, the reaming tool <NUM> may include a roadheader tool, which may scale and muck rock or other material that has been affected by a projectile impact. The reaming tool <NUM> may be associated with a boring assembly of the system <NUM>, which in some implementations may include a vehicle that is separate from the ram accelerator assembly <NUM>. In other implementations, the reaming tool <NUM> may be associated with the same vehicle or other type of assembly as the ram accelerator assembly <NUM> and positioned relative to the ram accelerator assembly <NUM> such that the reaming tool <NUM> may contact a portion of a workface that was affected by a projectile impact. For example, the reaming tool <NUM> may be used to smooth or extend the edges of a crater created by an interaction between a projectile and the workface. Material that is weakened by an impact with one or more projectiles may be considerably easier to remove using mechanical energy, such as the rotational movement or other movement of a cutting head on the reaming tool <NUM>, when compared to conventional boring using rotational movement of a drill or other type of reamer. Therefore, the wear on the cutting head of the reaming tool <NUM> and the mechanical rotational energy needed to remove material may be lower than the wear and energy associated with conventional boring operations.

In some implementations, the reaming tool <NUM> may be moved, oriented, aimed, and so forth, to contact a selected portion of a workface. For example, the reaming tool <NUM> may be oriented such that a cutting head thereof contacts a portion of the workface that was impacted by a projectile from the ram accelerator assembly <NUM>. Continuing the example, <FIG> depicts the reaming tool <NUM> associated with a boom <NUM> that is in turn associated with a pivoting or articulating joint <NUM>. The articulating joint <NUM> may enable the cutting surface(s) of the reaming tool <NUM> to be raised, lowered, and in some cases, moved in one or more lateral directions. In some implementations, the boom <NUM> may be extended and retracted (e.g., telescopically) to position the cutting surface(s) of the reaming tool <NUM> farther from or closer to the workface. The reaming tool <NUM> may also be moved toward or away from a workface using motive force. For example, the reaming tool <NUM> may include wheels <NUM>, treads, tracks, or other structures to facilitate movement thereof. In other implementations, the reaming tool <NUM> may be engaged with rails, tracks, or other similar structures. While <FIG> depicts a single reaming tool <NUM>, in other implementations, multiple reaming tools <NUM> may be used to extend a shaft or tunnel. The multiple reaming tools <NUM> may be associated with a single vehicle or boring assembly, or with multiple vehicles or assemblies. For example, multiple reaming tools <NUM> may be used to simultaneously bore through the same or different portions of a workface, such as to remove a large block of material from a workface.

In some implementations, a combination of projectile impacts and reaming tools <NUM> may be used to create a hole having dimensions larger than those of the reaming tool <NUM> or other equipment used to form a shaft or tunnel. For example, the ram accelerator assembly <NUM> may accelerate projectiles at an angle that is not parallel to the longitudinal axis of the tunnel or shaft, and the reaming tool <NUM> may be positioned to displace material from locations impacted by the projectiles. As a result, a hole having larger dimensions than the assemblies used to form the hole can be created without requiring conventional over-reamer mechanical systems.

A third assembly associated with the system <NUM> may include a collection assembly for collecting, transporting, displacing, or otherwise removing debris created by projectile impacts and by operations performed using the reaming tool <NUM> from the workface. In some implementations, a collection plate <NUM> may be associated with the collection assembly that includes the reaming tool <NUM>. For example, <FIG> depicts a collection plate <NUM> as a ramp, platform, or similar structure positioned below the reaming tool <NUM> in a position proximate to the ground beneath the reaming tool <NUM>. The collection plate <NUM> may catch or collect rock debris and other material from the workface created due to interactions between the workface and projectiles or the reaming tool <NUM>. For example, the collection plate <NUM> may extend at a downward angle from the reaming tool <NUM> to contact or be positioned close to a floor of a shaft or tunnel, such that as the reaming tool <NUM> is advanced toward the workface, the collection plate <NUM> is advanced beneath debris or into debris that has fallen along the floor of the shaft or tunnel. In some implementations, the collection plate <NUM> may include an extension, arm, or other feature for removing rock or other material from the path of the boring assembly that includes the reaming tool <NUM>, or other vehicles or assemblies, such as by leaving an undercut portion of a tunnel or shaft, which may prevent damage to components of the system <NUM>. In some implementations, the collection plate <NUM> may be movable in vertical directions, such as to position the collection plate <NUM> closer to a floor of a shaft or tunnel, or to raise the collection plate to cause movement of collected debris toward a guide ramp <NUM> located behind the collection plate <NUM>. For example, one or more joints <NUM> may also enable movement of the collection plate <NUM>. In some implementations, the collection plate <NUM> may also be movable in one or more lateral directions. Additionally, in some implementations, the collection plate <NUM> may be movable inward or outward relative to the boring assembly that includes the reaming tool <NUM>, such as through use of a boom <NUM> or another type of telescoping member. Movement of the boring assembly that includes the reaming tool <NUM> and collection plate <NUM> in a forward direction, such as through use of the wheels <NUM> or a similar member, may also be used to move the collection plate <NUM> closer to debris associated with a workface.

Movement of the collection plate <NUM> may move debris collected by the collection plate <NUM> toward the guide ramp <NUM>. In some implementations, at least a portion of the collection plate <NUM> or guide ramp <NUM> may include a conveyor belt or other mechanism for imparting motive force to debris. In other implementations, one or more of the collection plate <NUM> or guide ramp <NUM> may be pivotable to shift debris away from the collection plate <NUM> and toward the guide ramp <NUM>. In still other implementations, forward movement of the reaming tool <NUM> may function to move debris toward the guide ramp <NUM>. In yet other implementations, the reaming tool <NUM>, itself, or one or more arms associated with the collection plate <NUM> may be used to sweep debris and other materials into the connection plate <NUM>, and in some cases toward the guide ramp <NUM>. For example, the collection plate <NUM> may be associated with a wheeled or tracked system that is movable toward and away from a workface. In some implementations, the reaming tool <NUM> may be used to cause debris from selected portions of a tunnel to fall on or near the collection plate <NUM>. For example, the reaming tool <NUM> may be positioned near or in contact with portions of a workface, floor, ceiling, or walls of a tunnel to sweep broken rock and other debris into or near the collection plate <NUM>.

To facilitate removal of debris away from a workface, a collection trailer <NUM> or other type of movable receptacle may be positioned proximate to a rear end of the guide ramp <NUM>. The collection trailer <NUM> may include a chute, trough, guide, or other similar structure that may be used to collect debris from the guide ramp <NUM>. In some implementations, the chute, trough, or guide of the collection trailer <NUM> may impart motive force to debris, such as through use of a conveyor belt or similar device. For example, motive force associated with the collection trailer <NUM> may be used to move debris away from a workface and toward an entrance of a tunnel or shaft. In other implementations, the collection trailer <NUM> may be pivotable or angled to urge debris away from a workface using gravity. In still other implementations, the collection trailer <NUM> may be removed from a worksite using wheels, tracks, rails, or other mechanisms for enabling movement of the collection trailer <NUM>, to enable the collection trailer <NUM> to be emptied and returned, or replaced with an additional collection trailer <NUM>. In some implementations, the collection trailer <NUM> may be positioned behind the boring assembly that includes the reaming tool <NUM>, and one or more protruding or overhanging portions extending from the collection trailer <NUM> may be positioned above the reaming tool <NUM>, collection plate <NUM>, or guide ramp <NUM>, which may protect components thereof.

While <FIG> depicts the collection plate <NUM> and guide ramp <NUM> associated with the same assembly that includes the reaming tool <NUM>, in other implementations, the collection plate <NUM> and guide ramp <NUM> may be associated with a separate assembly. Additionally, while <FIG> depicts the collection trailer <NUM> as a separate assembly from the collection plate <NUM> and guide ramp <NUM>, in other implementations, the collection trailer <NUM>, or another type of movable receptacle, may be part of the same assembly as the collection plate <NUM> and guide ramp <NUM>. Any combination of the components described with regard to <FIG> may be combined in any number of assemblies. For example, the ram accelerator assembly <NUM> may be engaged with the collection trailer <NUM>, the boring assembly that includes the reaming tool <NUM>, and so forth. As such, while <FIG> depicts the ram accelerator assembly <NUM>, reaming tool <NUM>, and collection trailer <NUM> as discrete components, in various implementations, one or more of the components may be engaged with one another. For example, the reaming tool <NUM> may include a motor or other source of motive force and may be used to pull one or more of the collection trailer <NUM> or the ram accelerator assembly <NUM>. In other cases, the ram accelerator assembly <NUM> and collection trailer <NUM> may be separate from the reaming tool <NUM> and may be associated with a vehicle, a motor, or another source of motive force.

The system <NUM> shown in <FIG> may enable efficient and generally continuous boring operations by using accelerated projectiles from one or more ram accelerator assemblies <NUM> to at least partially weaken a working face, a reaming tool <NUM> to remove debris from an area of the workface affected by the projectiles, and a collection assembly and collection trailer <NUM> to remove debris from proximate to the workface while operation of the ram accelerator assembly <NUM> and reaming tool <NUM> is performed.

While <FIG> depicts a single ram accelerator assembly <NUM>, reaming tool <NUM>, and collection trailer <NUM>, in other implementations, an autonomous fleet that includes multiple vehicles may be used to more efficiently bore through a single workface. Additionally, multiple fleets of vehicles at multiple worksites may be coordinated remotely. For example, one or more of the ram accelerator assembly <NUM>, reaming tool <NUM>, or collection trailer <NUM> may be operated remotely or autonomously, without requiring personnel at a worksite.

In some implementations, the ram accelerator assembly <NUM> may be selectively used to bore through hard rock and similar materials, while the reaming tool <NUM> may be used independent of the ram accelerator assembly <NUM> to bore through softer materials, such as sand or lower strength rock. Use of the ram accelerator assembly <NUM> and reaming tool <NUM> selectively, to maximize one or more of stability (e.g., integrity of the walls or ceiling of a tunnel or shaft), speed, or cost may be controlled remotely or autonomously. Additionally, in some implementations, unintentional acceleration of projectiles by the ram accelerator assembly <NUM> or acceleration of projectiles by the ram accelerator assembly <NUM> that may not be beneficial may be prevented through use of one or more computing devices or other autonomous controls. For example, a controller associated with ram accelerator assembly <NUM> may be configured to only cause the ram accelerator assembly <NUM> to accelerate projectiles when a "heart-beat" signal is has been received from a computing device. In some implementations, a computing device or controller associated with the ram accelerator assembly <NUM> may be provided with one or more criteria, such as pressure, inclination, magnetic characteristics, or other types of digital or mechanical measurements. The ram accelerator assembly <NUM> may be prevented from actuation (e.g., acceleration of projectiles to impact a workface) if selected criteria are not met, or prevented from actuation if certain criteria are present, which may prevent acceleration of projectiles if the ram accelerator assembly <NUM> is not in a proper location or if use of projectile impacts may not provide a significant benefit. In some implementations, the ram accelerator assembly <NUM> may be associated with accelerometers, laser ring gyros, a GPS, radio guidance systems, imaging systems (e.g., optical systems, cameras, etc.), and so forth, to enable a remote user or autonomous system to determine an optimal time to accelerate a projectile, and to aim the accelerated projectile at a particular portion of a workface. Use of computer-controlled components may improve accuracy when the ram accelerator assembly <NUM> is used, such as enabling a projectile to accurately impact a workface even while portions of the system <NUM> are moving.

In some implementations, an acoustic signal generated by an impact between a projectile and a workface may be used to determine characteristics of rock or other material, which may be used to control the direction in which a tunnel or shaft is extended. For example, a tunnel or shaft may be preferentially extended toward rock having greater porosity or a lower density to facilitate faster boring operations, toward or away from subterranean water, and so forth. Example systems and methods for determining acoustic signals generated by projectile impacts and controlling extension of shafts based on this information are described in <CIT>.

<FIG> depicts an implementation of a method <NUM> by which projectiles <NUM> may be moved from a chamber <NUM> used to house the projectiles <NUM> into a barrel <NUM> from which the projectiles <NUM> may be accelerated toward a workface. Impacts <NUM> between a projectile <NUM> and a workface may create a fluid flow <NUM> that causes movement of other projectiles <NUM> from the chamber <NUM> toward the barrel <NUM>.

Specifically, <FIG> depicts an impact <NUM> between a first projectile <NUM>(<NUM>) and a workface, which may create a fluid flow <NUM>, in which fluid is directed toward an opening in the barrel <NUM> from which the projectile <NUM>(<NUM>) exited the barrel <NUM>. The fluid flow <NUM> may move a second projectile <NUM>(<NUM>) from a position in front of the chamber <NUM> toward the front of the barrel <NUM>, as indicated by an arrow representing the movement <NUM> of the second projectile <NUM>(<NUM>). The movement <NUM> of the fluid and second projectile <NUM>(<NUM>) may seat the second projectile <NUM>(<NUM>) within the barrel <NUM>, such that one or more seals <NUM> associated with the projectile <NUM>(<NUM>) engage the inner diameter of the barrel <NUM>. In some implementations, the seals <NUM> of the projectile(s) <NUM> may also engage the inner diameter of the chamber <NUM> when the projectile(s) <NUM> are positioned therein. After the second projectile <NUM>(<NUM>) is seated in the barrel <NUM>, actuation of a propellant material within the barrel <NUM> may accelerate the second projectile <NUM>(<NUM>) toward the workface to generate an impact <NUM>, which may in turn cause fluid flow <NUM> to facilitate movement of an additional projectile <NUM> into the barrel <NUM>. In some implementations, the fluid flow <NUM> may cause a flapper valve or other type of closure mechanism associated with the chamber <NUM> or barrel <NUM> to close to prevent excess fluid, debris, or air from entering the chamber <NUM> or barrel <NUM>.

While <FIG> depicts an implementation in which fluid flow <NUM> moves projectiles <NUM> toward a front of the barrel <NUM>, in other implementations, projectiles <NUM> may be moved toward a back end of the barrel <NUM>, or a side opening of the barrel <NUM> (e.g., breech loading). Additionally, while <FIG> depicts movement of projectiles <NUM> from a chamber <NUM> to a barrel <NUM>, in other implementations, a slurry of projectiles <NUM> may be pumped through tubes toward the barrel <NUM> of the ram accelerator assembly <NUM>. In still other implementations, one or more projectiles <NUM> may be generated on-site. For example, the ram accelerator assembly <NUM> or another assembly associated with the system <NUM> may fill a plastic container or other type of container with concrete, another curable material, or a dense liquid, and the filled container may be used as a projectile <NUM>.

In some implementations, one or more of the projectiles <NUM> may include a tapered tip <NUM> to facilitate penetration into a workface. Projectiles <NUM> may also include a generally cylindrical body <NUM>, and a rear face <NUM> that facilitates acceleration of the projectile <NUM> and reduces drag. In some implementations, characteristics of the projectiles <NUM>, such as exterior features of the body of a projectile <NUM>, may interact with characteristics of the barrel <NUM> to produce a ram effect as the projectile(s) <NUM> are accelerated through the barrel <NUM>.

In some implementations, one or more of the ram accelerator assembly <NUM>, reaming tool <NUM>, or collection trailer <NUM> may be operated under a gas or liquid pressure, such as under water, within drilling mud, or in pressurized air, which may increase the buoyancy of debris and conveyance of the debris away from the workface. Increased pressure may also facilitate the stability of a tunnel or shaft, reducing or eliminating a need for rock bolting or other types of ground support. For example, rock and other materials may be more buoyant when submerged in water, drilling mud, or pressurized air, which may enable components of an assembly for conveying debris away from a workface to be lighter and to operate using less force and energy. Additionally, operation of portions of the system <NUM> within a fluid may reduce or eliminate the need to empty a tunnel of water. Reducing or eliminating the need for water discharge operations may increase efficiency and lower costs related to the extension of a tunnel or shaft. Further, the system <NUM> may be used in a sloped area (e.g., an incline or a decline), to extend a horizontal tunnel or shaft, or to extend a curved tunnel or shaft. Use of projectiles <NUM> accelerated using the ram accelerator assembly <NUM> may enable projectiles <NUM> to accurately impact a targeted location even when used under pressure, within a fluid, and so forth. For example, while a projectile <NUM> may lose velocity when traveling through certain media, a projectile <NUM> accelerated using a ram accelerator assembly <NUM> may maintain sufficient velocity to accurately impact a target.

In some implementations, tunnel stabilization mechanisms, such as a rock bolting tool for placing rocks bolts, nails, or other stabilizing structures into a wall of a tunnel, a shotcreting tool for providing concrete, mortar, or other materials to a tunnel wall, or other types of tools may be incorporated into one or more of the ram accelerator assembly <NUM>, reaming tool <NUM>, or collection trailer <NUM>. Use of bolting and shotcreting tools, or other types of tunnel stabilization mechanisms, may allow a continuous mining, tunneling, or boring operation to be performed by enabling stabilization and ground support processes to be performed at least partially simultaneously with the acceleration of projectiles, boring of a tunnel or shaft using a reaming tool <NUM>, and removal of debris using the collection plate <NUM> and other portions of the collection assembly.

For example, <FIG> and <FIG> depict example systems <NUM>, <NUM>, in which the collection trailer <NUM> includes a muck conveyor <NUM> used to move debris away from a workface, and a shotcrete crawler <NUM> and nailing/bolting crawler <NUM> engaged with guided structures above the muck conveyor <NUM>. The muck conveyor <NUM> may include a chute, ramp, or other structure for guiding debris away from a workface. In some implementations, the much conveyor <NUM> may include a conveyor belt or other system for providing motive force to debris. The shotcrete crawler <NUM> and nailing/bolting crawler <NUM> may perform stabilizing operations within a tunnel or shaft as the collection trailer <NUM> is advanced within the tunnel or shaft. Specifically, the nailing/bolting crawler <NUM> may be used for bolting operations, while the shotcrete crawler <NUM> may be used to provide mortar or other stabilizing materials within the tunnel. While <FIG> and <FIG> depict the shotcrete crawler <NUM> and nailing/bolting crawler <NUM> being associated with an assembly for removal of debris from a workface, in other implementations, the shotcrete crawler <NUM>, nailing/bolting crawler <NUM>, or other tools or assemblies may be associated with the ram accelerator assembly <NUM>, the assembly that includes the reaming tool <NUM>, or separate assemblies or vehicles.

In some implementations, one or more of the assemblies for performing continuous tunneling, boring, or mining operations described with regard to <FIG> may be combined or incorporated in different manners. For example, the reaming tool <NUM> and ram accelerator assembly <NUM> may be incorporated within a single assembly.

<FIG> is a series of diagrams <NUM> depicting an implementation of a cutting tool <NUM> that may be used in conjunction with a ram accelerator assembly <NUM> to extend a shaft or tunnel using a combination of projectile impacts and boring operations. In some implementations, the cutting tool <NUM> may include a drill bit, such as a rock bit, coring bit, or other type of drill bit having one or more cutting elements that are brought into contact with rock or other material, and that cut or displace the material through rotation of the drill bit. For example, the cutting tool <NUM> is shown having a generally cylindrical body with a cutting surface <NUM> at an end thereof. The cutting surface <NUM> may include one or more cutting elements that cut, ream, or otherwise displace rock or other material adjacent to the cutting surface <NUM> as the cutting surface <NUM> is rotated. The cutting surface <NUM> may also include one or more orifices through which projectiles <NUM> may be accelerated into contact with a workface adjacent to the cutting surface <NUM>. For example, one or more ram accelerator assemblies <NUM> may be incorporated within the body of the cutting tool <NUM>.

Continuing the example, <FIG> depicts a diagrammatic front view of the cutting surface <NUM> in which a series of orifices through which accelerated projectiles <NUM> may pass through the cutting surface <NUM>. In some implementations, each orifice may be associated with a ram accelerator assembly <NUM>. In other implementations, a single ram accelerator assembly <NUM> may be configured to accelerate projectiles <NUM> through multiple orifices.

Specifically, <FIG> depicts an implementation in which a series of radial projectile orifices <NUM> are generally evenly spaced about a circumference of the cutting surface <NUM>. The cutting surface <NUM> is shown including an outer ring of eight radial projectile orifices <NUM> and an inner ring of eight radial projectile orifices <NUM> positioned inward relative to the outer ring. The cutting surface <NUM> is also shown including two central projectile orifices <NUM>, which in some implementations may have a larger diameter than that of the radial projectile orifices <NUM>. For example, projectiles <NUM> accelerated through the central projectile orifice(s) <NUM> may have one or more dimensions greater than projectiles <NUM> accelerated through the radial projectile orifice(s) <NUM>.

In some implementations, the particular orifices through which projectiles <NUM> are accelerated may be selected based on the characteristics of the material through which the cutting tool <NUM> is penetrating, the direction in which a tunnel or shaft is extended, the rate at which it is desired to extend a tunnel, and so forth.

For example, <FIG> is a diagram <NUM> depicting a system for extending a tunnel <NUM> using multiple ram accelerator assemblies <NUM> in combination with the cutting surface <NUM> of a cutting tool <NUM>. In <FIG>, the body of the cutting tool <NUM> is not shown to enable visualization of the position of the cutting surface <NUM> and ram accelerator assemblies <NUM>. <FIG> depicts four ram accelerator assemblies <NUM> arranged in a row. In some implementations, the cutting surface <NUM> may rotate relative to the ram accelerator assemblies <NUM>, and when orifices in the cutting surface <NUM> are aligned with the ram accelerator assemblies <NUM>, at least a portion of the ram accelerator assemblies <NUM> may be actuated to accelerate one or more projectiles <NUM> through the orifices.

<FIG> depicts one or more additional vehicles <NUM> associated with the cutting tool <NUM> and ram accelerator assemblies <NUM>. For example, the ram accelerator assembly <NUM> may be advanced through the tunnel <NUM> using wheels <NUM>, tracks, rails, and so forth, and the vehicles <NUM> may similarly include wheels <NUM> or another mechanism for advancement through the tunnel <NUM>. In some cases, the vehicles <NUM> may be associated with assemblies that support use of the cutting tool <NUM> or ram accelerator assemblies <NUM>, such as assemblies that provide projectiles <NUM> and propellant materials into the ram accelerator assemblies <NUM>. Additionally, in some cases, the vehicles <NUM> may be associated with assemblies for collecting and removing debris created by interactions between the cutting surface <NUM> or the projectiles <NUM> and a workface.

In some implementations, the specific ram accelerator assemblies <NUM> that are actuated may be selected based on a desired direction in which to extend the tunnel <NUM>. For example, repeatedly accelerating projectiles <NUM> toward one side of the cutting surface <NUM> may cause the tunnel <NUM> to be extended in an opposing direction due to the force exerted by the acceleration of the projectiles <NUM> and the interaction between the projectiles <NUM> and one side of the tunnel <NUM>. In other implementations, the specific ram accelerator assemblies <NUM> that are actuated may be selected based on the characteristics of the material through which the cutting surface <NUM> is penetrating, a desired rate of penetration, and so forth. For example, a smaller number of ram accelerator assemblies <NUM>, and in some cases zero ram accelerator assemblies <NUM>, may be actuated at times when a sufficient rate of penetration may be achieved using the cutting tool <NUM>.

<FIG> is a series of diagrams <NUM> depicting example implementations in which different numbers or configurations of ram accelerator assemblies <NUM> may be used based on the characteristics of a workface, a desired rate of penetration, or a desired shape of penetration. In a first diagram, a large portion of a workface in front of the cutting surface <NUM> may be affected by projectile impacts by actuating a large number of ram accelerator assemblies <NUM> associated with the cutting tool <NUM>, as illustrated by a first set of projectile paths <NUM>. In such a case, a large portion of a rock face or other type of workface may be impacted by multiple projectiles <NUM>, which may substantially weaken a large portion of the workface. In a second diagram, a selected subset of ram accelerator assemblies <NUM> may be actuated, as illustrated by a second set of projectile paths <NUM>, which may weaken a selected portion of a workface. Weakening of a selected portion of a workface using projectile impacts may be used to control the rate of penetration through a material, the shape of a tunnel <NUM> formed in the material, the direction in which a tunnel <NUM> is extended, and so forth. For example, interaction between a cutting surface <NUM> and a first portion of a workface that has not been weakened by a projectile impact may cause the path of the cutting tool <NUM> to be diverted way from the first portion of the workface, and toward a second portion of the workface that has been weakened by a projectile impact. Projectile impacts may also be used to selectively impact the center of a workface, the edges of a workface, or other portions of a workface.

For example, a portion of a workface, such as the percentage of an area of a hole, that is to be weakened by projectiles <NUM> may be selected, while the remainder of the workface may remain to be removed using drilling or boring operations using a cutting surface <NUM>. The portion of the workface that is weakened by projectiles <NUM> may be selected based on the rate at which a tunnel <NUM> or shaft may be extended using a cutting tool <NUM> and the rate at which debris may be removed from a workface. For example, if a tunnel <NUM> is extended at a rate that enables debris to accumulate more rapidly than the debris may be removed, use of projectiles <NUM> to weaken the workface may be limited to conserve materials and slow the rate of penetration through a workface, preventing undesired accumulation of debris.

For example, projectiles <NUM> may be accelerated using radial projectile orifices <NUM> associated with a cutting surface <NUM>, creating a disc-shaped region of a workface that is affected by projectile impacts, while leaving a central portion of the workface unaffected by projectile impacts.

<FIG> is a diagram <NUM> depicting a workface <NUM> in which an outer region <NUM> has been affected by one or more projectile impacts <NUM>, as illustrated by projectile paths <NUM>, while an inner region <NUM> is not affected by projectile impacts <NUM>. As a result, the inner region <NUM> may primarily be impacted by the cutting surface <NUM> of a cutting tool <NUM>, as illustrated by the region of <FIG> labeled "cutting interactions" <NUM>. In some implementations, a disc-shaped cutting surface <NUM> having a diameter perpendicular to the workface <NUM> may be used to remove material from the workface <NUM>. In such a case, projectiles <NUM> accelerated as illustrated by the projectile paths <NUM> may break or condition material on both sides of the area where the disc-shaped cutting surface <NUM> may contact the workfare <NUM>, which may reduce stress on both sides of the disc-shaped cutting surface <NUM>.

In some implementations, one or more of the systems described with regard to <FIG> may be used in conjunction with a mobile (e.g., self-driven or autonomously-controlled) tunneling unit. Traditional tunnel boring machines (TBMs) include round cutterheads and use rotary torque to carve through rock or other material. An excavation process that uses TBMs typically creates a concentric hole, limiting applications into a single cross-section type and ultimately producing a profile with a low utilization ratio of tunneled sections. In cases where a project requires a finished tunnel cross-section that is not circular (such as rectangular or other shapes), a secondary excavation operation is typically used to provide the desired cross-section. The additional equipment, labor, and time associated with a secondary excavation operation can exponentially increase the time, cost, and other resources associated with forming a tunnel. Implementations described herein may enable tunnels to be formed and conditioned, such as through trenchless excavation operations, and may provide tunnels with cross-sectional shapes that are circular or non-circular, with a significantly higher utilization ratio for tunnel sections than conventional excavation operations. In some implementations, the techniques described herein may be used to form a tunnel having varying geometry (e.g., a tunnel that changes in diameter or cross-sectional shape as a function of length). Additionally, use of techniques described herein may enable tunnels to be formed and conditioned with significantly less time and cost when compared to conventional excavation operations.

In some implementations, such a tunneling unit may use water jet cutters, or other media or devices, to precondition a surface, while ram accelerator assemblies <NUM> may be used to break rock or other materials by accelerating projectiles <NUM> into contact with the material. In some implementations, the water jet cutters and ram accelerator assemblies <NUM> may be controlled remotely, and in some cases may be articulated or aimed in a variety of positions. As described previously, a ram accelerator assembly <NUM> may weaken, break, degrade, or otherwise affect rock or other materials, which may enable other tools to more effectively displace the material. Additionally, while the ram accelerator assembly <NUM> is described using the term "ram accelerator", a rail gun, gas gun, or other method of providing force to projectiles <NUM> may also be used. As described previously, a ram accelerator assembly <NUM> may include a tubular body having a propellant or other source of motive force, such as a gas gun, positioned in association therewith, such that force from pressurized or combustible gas may move a projectile <NUM> within the tubular body. Then, interactions between the projectile <NUM> and the tubular body may further accelerate the projectile <NUM> toward a rock face or other material. Interactions between the projectiles <NUM> and rock or other material may break the material into a desired cross-sectional shape. In some implementations, a surface may be preconditioned prior to impact with one or more projectiles <NUM> to control the manner in which projectile impacts cause the material to break or otherwise be affected.

<FIG> is a series of diagrams <NUM> illustrating an implementation of a tunneling unit <NUM> that may be used to condition a surface and displace material from the surface using a combination of water jets <NUM> and ram accelerator assemblies <NUM>. The tunneling unit <NUM> may include a structural frame <NUM> that is movable forward and backward (e.g., to advance further into and out from a tunnel <NUM>) using tracks <NUM>. In other implementations, wheels, skids, rollers, or other methods for enabling movement of the tunneling unit <NUM> may be used. In some implementations, movement of the tunneling unit <NUM> may be controlled remotely. In some implementations, the tunneling unit <NUM> may be configured for automatic movement, such as automatic advancement deeper into a tunnel after use of the tunneling unit <NUM> to form a segment of a tunnel <NUM>.

Multiple water jets <NUM> may be mounted on the structural frame <NUM>. In some implementations, the water jets <NUM> may include articulating water jet heads (e.g., water jet cutters). In other implementations, other types of cutting, reaming, or boring tools may be used to pre-condition a surface in addition to or in place of the water jets <NUM>. One or more ram accelerator assemblies <NUM> may also be mounted to the structural frame <NUM>. <FIG> depicts the structural frame <NUM> having an outer frame with a generally rectangular shape, upon which the water jets <NUM> are mounted, and an inner frame having a generally semicircular shape, upon which the ram accelerator assemblies <NUM> are mounted. However, in other implementations, frames having any shape may be used. For example, water jets <NUM> may be positioned along an outer frame having a semicircular shape, or another desired shape. As another example, both water jets <NUM> and ram accelerator assemblies <NUM> may be positioned along a single frame having a rectangular shape, a semicircular shape, or another shape, and use of separate inner frames and outer frames may be omitted.

In some implementations, as shown in <FIG>, the water jets <NUM> may be mounted at a leading (e.g. front) edge of the tunneling unit <NUM>, while the ram accelerator assemblies <NUM> are mounted behind the water jets <NUM>, such as at or near a trailing (e.g., rear) edge of the structural frame <NUM>. In some implementations, a rack system may allow each water jet <NUM> to move independently, articulate, and achieve multiple different positions or orientations to project water toward a surface. Each water jet <NUM> may include an actuator, and in some implementations, may be programed to move automatically, independent of other water jets <NUM>. For example, a particular water jet <NUM> may be programmed to run a set task that includes articulating to one or more positions, use of one or more travel rates, feed or flow rates, and other operational parameters. Continuing the example, a tunneling unit <NUM> having multiple water jets <NUM> may be programmed to use the water jets <NUM>, in conjunction with one another, to pre-condition rock or other material for formation of a section of a tunnel <NUM>.

In some implementations, the tunneling unit <NUM> may include one or more additional water jets <NUM> located toward the bottom of the tunneling unit <NUM> that may be attached to movable arms. In some implementations, such a water jet <NUM> may be mounted on a six-axis robotic arm, which may allow the water jet <NUM> to be positioned and oriented in a nearly-infinite number of ways to provide water toward rock or other material. In other implementations, other types of arms or movable members, including arms with greater or fewer than six axes, may be used. As the tunneling unit <NUM> is advanced into a tunnel <NUM>, these water jets <NUM> may precut a lower portion of a tunnel profile, then be moved out of position as needed for other operations.

In some implementations, the water jets <NUM> may be used to cut an initial outer profile for a tunnel section. In other implementations, the water jets <NUM> may be used to cut other patterns to pre-condition or weaken a rock face or other material. After cutting an initial outer profile, the ram accelerator assemblies <NUM>, which in some implementations may be articulated, aimed, and so forth, may be used to accelerate projectiles <NUM> into the rock or other material, within the outer profile, to pulverize the material. In some implementations, each ram accelerator assembly <NUM> may be associated with a track <NUM> or other mechanism to enable movement thereof, and may be moved, pivoted, and articulated to provide projectiles to selected positions in the rock or other material. As the rock or other material is broken by projectile impacts, mucking operations, such as those described with regard to <FIG>, may be used to transport the material out from the newly-formed tunnel section. The tunneling unit <NUM> may then be moved forward into the newly-formed tunnel section, and the process may be repeated to extend the tunnel <NUM>. In some implementations, the tunneling unit <NUM> may be continuously advanced as sections of a tunnel <NUM> are formed. Extension of the tunnel <NUM> by repeating this process may be used to provide a subsequent tunnel section having the same cross-sectional shape and diameter, or a different (or variable) cross-sectional shape or diameter.

<FIG> is a diagram <NUM> illustrating a perspective view of the tunneling unit <NUM> of <FIG> positioned to interact with and form a tunnel <NUM> within a workface <NUM>, such as a rock face or other type of material or surface. As described previously, the tunneling unit <NUM> may include one or more water jets <NUM> at the leading (e.g., front) end thereof, and ram accelerator assemblies <NUM> at or near a trailing (e.g., rear) end thereof. The water jets <NUM> may be positioned on an outer portion of a structural frame <NUM> of the tunneling unit <NUM>, which may have a generally rectangular shape, while the ram accelerator assemblies <NUM> are positioned on an inner portion of the structural frame <NUM> having a generally semicircular shape. The tunneling until <NUM> may be positioned on tracks <NUM> or a similar component to enable movement of the tunneling unit <NUM> into or out from a tunnel <NUM>.

In some implementations, the water jets <NUM> may be used to pre-condition a portion of a rock face or other material having a non-circular profile, such as a square or rectangular cross-sectional shape. For example, <FIG> depicts a diagram <NUM> in which a tunnel profile <NUM> for a tunnel <NUM> may be formed using pre-conditioning devices, while a projectile shot pattern <NUM> may be used to displace material to form a section of a tunnel <NUM> based on the tunnel profile <NUM>. After pre-conditioning a portion of the rock face using the water jets <NUM>, one or more ram accelerator assemblies <NUM> may then be used to fire projectiles <NUM> into the workface <NUM> or other material at locations within the pre-conditioned profile formed by the water jets <NUM>. Interactions between the projectiles <NUM> and the workface <NUM> or other material may break, pulverize, or otherwise degrade the material, forming a tunnel section having the shape of the pre-conditioned profile. Mucking operations may then be used to remove the degraded material from the tunnel <NUM> to enable advancing of the tunneling unit <NUM>. Due to the generally open interior of the tunneling unit <NUM>, mucking operations, as well as other operations, may be performed without requiring removal of the tunneling unit <NUM>, such as by passing personnel or equipment beneath the structural frame of the tunneling unit <NUM>.

While <FIG> depict a tunneling unit <NUM> that includes water jets <NUM>, in other implementations, other methods for pre-conditioning or cutting a rock face or other material may be used. For example, rock saw blades, rotating cutters, disc cutters, road headers, water jets with added abrasives, thermal spallation, thermal conditioning (e.g., heating and breaking rock), plasma jet cutters, pre-drilling, and so forth may be used in addition to or in place of water jets <NUM> to cut or pre-condition a desired profile. In some implementations, ram accelerator assemblies <NUM> or other projectile-firing devices may be used to cut or pre-condition a rock face or other material. For example, projectile impacts may be used to form holes around the perimeter of a desired profile in a rock face.

Use of water jets <NUM> or other mechanisms to pre-condition or pre-cut a rock face or other material in a desired cross-sectional shape may increase the efficiency of rock breaking operations. For example, by using water jets <NUM> to form a square or rectangular perimeter shape, or another desired shape for the cross-section of a portion of a tunnel <NUM>, the breakage of rock using projectile impacts from the ram accelerator assemblies <NUM> may be controlled. Continuing the example, breakage caused by projectile impacts may be limited to a pre-cut or pre-conditioned region of rock, thereby controlling the shape of the material that is removed from a workface <NUM>. In some implementations, the gain and near-bore rock damage may be controlled by use of the water jets <NUM> to create a gap, or a region of weakened rock or rock having a different density. The region of the rock affected by the water jets <NUM> may simulate a free face reflection zone so that a shock wave caused by a projectile impact changes from a compression wave to a tension wave, which pulls and breaks the pre-conditioned rock along the perimeter defined by the pre-conditioning of water jets <NUM>. For example, creation of a cut or pre-conditioned region of rock may provide a boundary zone where, when metallic, ceramic, erodible, or explosive-tipped projectiles, or other types of projectiles, are fired, the projectiles impact rock within the pre-conditioned region, creating a compression wave that is affected by the cut or weakened region of rock as described above. In other implementations, shock waves may be created using other mechanisms in addition to or in place of projectile impacts, such as through use of dynamite or other explosives. Use of the implementations described herein may more efficiently pre-condition a rock face for breakage compared to conventional methods, and more efficiently break the rock face using projectile impacts, which may be timed and spaced in a manner that controls the shockwaves of the impacts and creates a region for broken rock or other material to fall.

For example, <FIG> is a diagram <NUM> illustrating an implementation of interactions between projectiles <NUM> accelerated using ram accelerator assemblies <NUM> and a preconditioned portion of a tunnel <NUM>. A ram accelerator assembly <NUM> may include a propellant chamber <NUM> for providing propellant material to one or more other portions of the ram accelerator assembly <NUM> to impart a force to a projectile <NUM>. In some implementations, the propellant chamber <NUM> may include a gas gun or other source of motive force. A vent section <NUM> may include one or more blast ports or other openings to enable gas created by pressurization, combustion, a chemical reaction, or other interactions with a propellant material to exit the ram accelerator assembly <NUM>. Interactions between the propellant material and the projectile <NUM> may accelerate the projectile <NUM> through a launch tube <NUM> of the ram accelerator assembly <NUM> into contact with rock or another material, causing a projectile impact <NUM> to break or weaken the material. In some implementations, interactions between the interior of the launch tube <NUM> and exterior features of the projectile <NUM> may impart a ram effect to the projectile <NUM> to increase the speed thereof. For example, the interior of the launch tube <NUM> may include baffles, rails, variations in the interior diameter of the launch tube <NUM>, or other features that interact with the body of the projectile <NUM> to increase the speed of the projectile.

In some implementations, multiple projectiles may impact different parts of a pre-conditioned region of a rock face or other material to break the material, as described above, forming debris that may be removed from the resulting tunnel section using mucking operations or other methods of transport or removal. For example, a tunnel profile <NUM> of the tunnel section may be formed using water jets <NUM> or other pre-conditioning devices. The tunnel section may be extended by breaking the pre-conditioned region within the tunnel profile <NUM> using projectile impacts. The resulting tunnel section may have a cross-sectional shape determined based on the pre-conditioning of the rock or other material using water jets <NUM> or other methods of cutting or pre-conditioning. In some implementations, a single ram accelerator assembly <NUM> may be used to accelerate multiple projectiles <NUM> into a rock face or other material, at the same location or at multiple different locations. For example, a single ram accelerator assembly <NUM> may be used in succession to provide projectiles <NUM> to various regions of a rock face. In other cases, multiple ram accelerator assemblies <NUM> may be used, sequentially or simultaneously, to impact the same or different regions of a rock face or other material with projectiles <NUM>. For example, the projectile shot pattern <NUM> shown in <FIG> may be applied to a rock face using multiple different ram accelerator assemblies <NUM> to accelerate projectiles <NUM> simultaneously or close-in-time.

Providing a rock face or other workface <NUM> with a pre-cut region, such as a region having a square shape, may cause plastic strain from a projectile impact to extend into the pre-cut portion of the rock face. For example, providing the bottom of a hole or the end of a tunnel <NUM> with a square-shaped pre-cut region prior to impacting a workface <NUM> with one or more projectiles <NUM> may facilitate changing the cross-sectional shape of subsequent portions of the hole or tunnel <NUM>. Formation of a pre-conditioned or pre-cut region, using water jets <NUM>, rock saws, impacts from projectiles <NUM>, or other methods described above, may be performed as discrete processes, or a continuous process. For example, water jets <NUM> or other mechanisms for pre-conditioning a workface <NUM> may be used continuously or in rapid succession between impacts from projectiles <NUM>. While implementations described herein include use of ram accelerator assemblies <NUM>, other mechanisms for accelerating projectiles may be used. For example, supersonic or hypersonic mass drivers, electric rail guns, or other devices may be used to accelerate projectiles <NUM> toward a workface <NUM>.

Implementations described herein may be used for formation of tunnels <NUM> that are horizontal, vertical, angled, or have other orientations. A tunnel <NUM> may also include a mine shaft, a vertical tunnel such as a borehole, or other types of holes or tunnels. Additionally, some implementations may include formation of tunnels <NUM> under water, or in other pressurized environments. Computing devices and sensors may be used to determine times and orientations for actuating water jets <NUM> or other pre-conditioning devices, and for actuating ram accelerator assemblies <NUM> or other methods for accelerating projectiles.

In some implementations, a rock face or other material may be broken first, such as by one or more projectile impacts <NUM>, prior to forming a pre-conditioned region using water jets <NUM> or other devices, then impacting the rock again to break the rock in a desired shape. In some implementations, if portions of a pre-conditioned region of a rock face or other material is not fully removed by projectile impacts, such as corner regions of a square-shaped pre-conditioned area, a scaling bar, jack hammer, drill bit, cutter, or other mechanical implement may be used to remove remaining material from the pre-conditioned region. In some cases, a water jet <NUM> may be used to remove the remaining material, such as by cutting the material in a radial direction. In other cases, additional projectile impacts may be used to remove material not removed by the initial projectile impacts <NUM>. For example, a smaller projectile impact <NUM> (e.g., using a smaller projectile, less force, or a projectile having different characteristics) may be used to remove remaining material not fully removed by an initial projectile impact <NUM>. In some implementations, water jets <NUM> may be articulated to project water in directions that are not parallel with the centerline of the tunnel face, such as to provide better control of the location of the edge of a pre-conditioned region during firing of the water jets.

While implementations described above with regard to <FIG> depict a single unit that includes water jets <NUM>, ram accelerator assemblies <NUM>, and so forth, in other implementations, a system that includes a projectile accelerating device, pumps, power, robotics, pre-conditioning devices, and so forth may include multiple separate units that may be controlled and coordinated using one or more computing devices. For example, sensors and other instrumentation may be used to remotely control and coordinate operations of various devices, manually or autonomously, such as to meet certain sets of parameters for rates of production. In some cases, an acoustic barrier, air barrier, gas barrier, or other type of separation may be provided between one or more pieces of equipment, such as to control dust, noise, and so forth.

In some implementations, multiple tunneling units <NUM> may be used in succession. For example, <FIG> is a diagram <NUM> depicting an implementation of a system that includes multiple tunneling units <NUM>. A first tunneling unit <NUM>(<NUM>) may include water jets <NUM> and ram accelerator assemblies <NUM>, as described with regard to <FIG>. A second tunneling unit <NUM>(<NUM>) may be positioned behind the first tunneling unit <NUM>(<NUM>) and may include a cutting surface <NUM> having a ring-shaped configuration. For example, the second tunneling unit <NUM>(<NUM>) may include a tunnel boring machine (TBM) with a ring cutter.

In some implementations, the first tunneling unit <NUM>(<NUM>) may be mounted to a generally cylindrical structural frame <NUM>. The second tunneling unit <NUM>(<NUM>) may be mounted to a generally cylindrical structural frame <NUM> having a larger diameter than that of the first tunneling unit <NUM>(<NUM>). For example, <FIG> depicts the first tunneling unit <NUM>(<NUM>) having water jets <NUM> at a front end, ram accelerator assemblies <NUM> at a back end, and noise-reducing baffles <NUM> behind the ram accelerator assemblies <NUM>. In some implementations, noise-reducing baffles <NUM> may be installed in a terminal bulkhead of the first tunneling unit <NUM>(<NUM>). Bulkheads and baffles may be used to acoustically isolate the first tunneling unit <NUM>(<NUM>), reducing the effect of noise caused by rock breaking and firing of projectiles occurring ahead of the second tunneling unit <NUM>(<NUM>) when it follows closely behind the first tunneling unit <NUM>(<NUM>). For example, the second tunneling unit <NUM>(<NUM>) may include a manned section having one or more human operators, and use of bulkheads, baffles, or both bulkheads and baffles may reduce the exposure of human operators to noise from rock breaking and firing of projectiles.

The first tunneling unit <NUM>(<NUM>) is shown in front of and spaced apart from the second tunneling unit <NUM>(<NUM>), which is shown positioned on a larger cylindrical frame <NUM>. The first tunneling unit <NUM>(<NUM>) and second tunneling unit <NUM>(<NUM>) may be spaced apart by a selected separation distance, such as for controlling noise, debris, and so forth. While <FIG> depicts the cutting surface <NUM> of the second tunneling unit <NUM>(<NUM>) having a ring-shaped configuration, in other implementations, the second tunneling unit <NUM>(<NUM>) may include an articulating cutter, such as a long wall miner or road header, disc cutters along a multiple rotation axis machine, and so forth. Because the first tunneling unit <NUM>(<NUM>) may be used to break the majority of rock to form a tunnel section, the second tunneling unit <NUM>(<NUM>) may have a variety of shapes that differ from those of traditional TBMs.

In some implementations, a conveyor system <NUM> may be incorporated within one or more of the tunneling units <NUM>. For example, a conveyor belt may be used to transport broken rock, debris, or other materials out from a tunnel <NUM>, and in some cases, to transport other materials into the tunnel <NUM>. In some cases, a rock crusher <NUM> or similar device may be positioned on or in front of the conveyor system <NUM> to crush, break, or otherwise degrade or process the broken rock or other debris transported using the conveyor system <NUM>. For example, <FIG> shows a rock crusher <NUM> positioned in association with a portion of a material handling conveyor system <NUM> within the structural frame <NUM> of the second tunneling unit <NUM>(<NUM>). In other implementations, a rock crusher <NUM> may be positioned within the structural frame <NUM> of the first tunneling unit <NUM>(<NUM>) in addition to or in place of a rock crusher <NUM> associated with the second tunneling unit <NUM>(<NUM>). For example, a projectile impact from the first tunneling unit <NUM>(<NUM>) may create sizeable pieces of debris that may be crushed or otherwise processed by a rock crusher <NUM> before providing the debris to pass through or into the second tunneling unit <NUM>(<NUM>). In some cases, both tunneling units <NUM> may constitute two independently controlled units that share a similar mucking methodology. For example, the tunneling units <NUM> may be independently controlled, while a single conveyor belt or other material conveying system may be used to move material associated with both tunneling units <NUM>.

During use, the first tunneling unit <NUM>(<NUM>) may be used to break a portion of a rock face, as described previously, forming a section of a tunnel <NUM>. The second tunneling unit <NUM>(<NUM>), being associated with a ring-shaped frame <NUM> having a larger diameter than that of the first tunneling unit <NUM>(<NUM>), may be used to ream the outer edges of the tunnel section created by the first tunneling unit <NUM>(<NUM>). As the tunneling units <NUM> are advanced into a newly-formed tunnel section, the second tunneling unit <NUM>(<NUM>) may ream or expand the outer edges of the tunnel section previously created by the first tunneling unit <NUM>(<NUM>).

<FIG> is a series of diagrams <NUM> showing front views of an implementation of the first tunneling unit <NUM>(<NUM>) and second tunneling unit <NUM>(<NUM>) of <FIG>. The first tunneling unit <NUM>(<NUM>) may include water jets <NUM> or other types of pre-conditioning devices, and ram accelerator assemblies <NUM> or other types of projectile acceleration devices, mounted to a structural frame <NUM>. In the implementation shown in <FIG>, the structural frame <NUM> has a generally cylindrical shape, however in other implementations, other shapes may be used. The water jets <NUM> may be used to pre-cut or pre-condition a rock face, such as by weakening a perimeter of a region of the rock face. Then, the ram accelerator assemblies <NUM> may be used to accelerate one or more projectiles <NUM> into the rock face within the perimeter. Impact between the projectiles <NUM> and the rock face may facilitate breakage of the rock within the perimeter, while the presence of the pre-cut or pre-conditioned perimeter may cause the shock waves caused by projectile impacts to pull and remove rock from the region of the rock face within the perimeter, as described previously. While <FIG> depicts the ram accelerator assemblies <NUM> positioned along an interior surface of a frame <NUM>, in other implementations, the ram accelerator assemblies <NUM> may be positioned along an outer surface of the frame <NUM>, or along a front edge of the frame <NUM>. Similarly, the water jets <NUM> may be positioned at other locations on the frame <NUM>.

The first tunneling unit <NUM>(<NUM>) may be a self-contained unit that may be used independently of the second tunneling unit <NUM>(<NUM>), and may be independently controllable from the second tunneling unit <NUM>(<NUM>). When the first tunneling unit <NUM>(<NUM>) is positioned close to a rock face, the depicted water jets <NUM> may be actuated to pre-condition the rock face in a full, <NUM>-degree profile. The ram accelerator assemblies <NUM>, also mounted around the circumference of the frame, may be used to break the preconditioned rock face by firing multiple projectiles into the rock face in succession. Projectile impacts may break the region of the rock face defined by the preconditioning of the water jets, causing sections of rock to fall within the newly-formed tunnel section. A conveyor system <NUM> within the first tunneling unit <NUM>(<NUM>) may be used to transport the material to mucking equipment located farther from the rock face.

In some implementations, the first tunneling unit <NUM>(<NUM>) may include a material-handling arm <NUM>, such as an excavator arm and bucket, which may be mounted to the leading edge of the frame of the first tunneling unit <NUM>(<NUM>). For example, the material-handling arm <NUM> may be remotely, automatically, or manually controllable to facilitate movement of broken rock or other materials away from or toward the rock face. While <FIG> depicts an excavator arm and bucket as an example device for conveying debris and other materials, other types of devices for moving material may also be used.

In some implementations, each water jet <NUM>, ram accelerator assembly <NUM>, the depicted material-handling arm <NUM>, and the conveyor system <NUM> shown in the first tunneling unit <NUM>(<NUM>) may be independently and automatically operated, such as remotely using controls outside of the tunnel <NUM> or in a manned portion of the second tunneling unit <NUM>(<NUM>) located behind the first tunneling unit <NUM>(<NUM>).

Additionally, <FIG> depicts a front view of the second tunneling unit <NUM>(<NUM>), which in some implementations may include a ring-shaped cutting surface <NUM> positioned along a generally cylindrical frame. In some implementations, the diameter of the ring cutter may be larger than that of the frame of the first tunneling unit <NUM>(<NUM>). For example, the cutting surface <NUM> of the second tunneling unit <NUM>(<NUM>) may further ream, weaken, degrade, smooth, or widen a section of tunnel after a rock face is initially broken using the first tunneling unit <NUM>(<NUM>). In other implementations, the second tunneling unit <NUM>(<NUM>) may include an articulating cutter, such as a long wall miner or road header, disc cutters along a multiple rotation axis machine, and so forth. Because the first tunneling unit <NUM>(<NUM>) is used to break the majority of rock to form a tunnel section, the cutting surface <NUM> of the second tunneling unit <NUM>(<NUM>) may have a variety of shapes that differ from those of traditional TBMs.

Broken rock or other materials broken by the first tunneling unit <NUM>(<NUM>), or by the second tunneling unit <NUM>(<NUM>), may pass through a central open section <NUM> of the second tunneling unit <NUM>(<NUM>). For example, the conveyor system <NUM> may pass through the open section <NUM> and may transport broken rock or other material away from or toward the rock face. As described previously, in some implementations, a rock crusher <NUM> or other device for breaking, crushing, or otherwise processing the broken rock or other debris may be associated with the conveyor system <NUM>.

In some cases, the ring-shaped cutting surface <NUM> of the second tunneling unit <NUM>(<NUM>) may act as a reamer that may clean and smooth the diameter of a tunnel section formed by using the first tunneling unit <NUM>(<NUM>) to break and remove rock. Through the center of the ring section, the continuous conveyor system <NUM> may be used to transport rock, debris, or other material from either tunneling unit <NUM> to a rock crusher <NUM> located behind the cutting surface <NUM> of the second tunneling unit <NUM>(<NUM>). The rock crusher <NUM> may process larger rock removed from the rock face by one or both tunneling units <NUM>. In some implementations, material processed by the rock crusher <NUM> may then be fed to an additional conveyor system <NUM> located behind the rock crusher <NUM> and transported toward a mucking system.

In other implementations, one or more ram accelerator assemblies <NUM> or water jets <NUM> may be incorporated within the frame of the second tunneling unit <NUM>(<NUM>). For example, ram accelerator assemblies <NUM> may be used to fire projectiles through a hole or lattice pattern within the ring shape of the second tunneling unit <NUM>(<NUM>).

In some implementations, a tunneling unit <NUM> may be used in combination with a pressurized exhaust system, such as a system that includes one or more pressurized screw augers. For example, a pressurized screw auger or another similar device may be used to transfer broken rock created by projectile impacts through a pressure-acoustic barrier within which the tunneling unit <NUM> may operate. This may enable the tunneling unit to be operated at different pressures, as well as control the passage of exhaust gasses separately, transmit or direct the flow of exhaust gasses, and so forth.

Although certain steps have been described as being performed by certain devices, processes, or entities, this need not be the case and a variety of alternative implementations will be understood by those having ordinary skill in the art.

Claim 1:
A system (<NUM>, <NUM>, <NUM>) comprising:
a cutting tool (<NUM>) having a cutting surface (<NUM>); and
a first launch tube (<NUM>) associated with a first projectile (<NUM>) and first propellant material for accelerating the first projectile toward a first region of geologic material, wherein the first projectile passes through at least one first orifice (<NUM>) having a first diameter, in the cutting surface to contact the first region of the geologic material, and the cutting surface contacts the first region after the contact between the first projectile and the first region; and
a second launch tube associated with a second projectile that is larger than the first projectile, wherein the second launch tube is positioned to accelerate the second projectile through at least one second orifice (<NUM>) having a second diameter larger than the first diameter.