Systems for forming or extending a tunnel or shaft within a working surface may include a ram accelerator assembly for accelerating a projectile into geologic material to weaken a region of the geologic material. A cutting tool may then be used to remove the weakened material more rapidly, with lower energy use and less wear on the cutting tool than use of the cutting tool independently. A collection assembly may be used to move debris away from the working surface while the projectile and cutting operations are performed to enable generally continuous use of the system. The number of projectiles that are accelerated and the rate at which projectiles are used may be controlled based on characteristics of the geologic material and the rate at which created debris may be removed, allowing an operation to be optimized for speed, cost, stability, or other factors.

A hole in geologic material, such as a wellbore, may be extended by impacting the working face of the hole with high velocity projectiles. A tube may be placed within the hole, and the lower end of the tube may be sealed to prevent ingress of material from the hole into the tube. A projectile may be accelerated through the tube, such as by igniting a combustible gas mixture to impart a force to the projectile. The impact of the projectile may extend the hole. In some cases, accelerated projectiles may be used in conjunction with a drill bit to drill a wellbore or other type of hole.

Systems for drilling or tunneling include an assembly for accelerating a projectile through a first conduit into a region of geologic material, which generates debris. The debris may be reduced in size by moving the debris to a crushing device located in a second conduit using a conveying device, such as an auger. The reduced-size debris is then moved toward the surface using fluid movement. A third conduit may be used to provide and remove material from the bottom of the first conduit to control pressure at the end of the conduit to prevent ingress of material into the first conduit. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

Systems for forming or extending a tunnel or shaft within geologic material may include a ram accelerator assembly for accelerating one or more projectiles into geologic material to weaken a region of the geologic material. The projectile(s) pre-condition the geologic material, such as by forming one or more holes in a central region of the material or to define a perimeter of the region to be displaced. A cutting tool or subsequent projectile impacts may then be used to remove the weakened material. The voids formed by the first projectile(s) cause compressive forces from subsequent impacts or cutting operations to be converted to tension forces that more efficiently break geologic material, which may fall into the voids created by the first projectile(s). The voids created by the projectile impacts may also control the material that is removed and the shape of a resulting section of the tunnel or shaft.

Systems for forming or extending a tunnel or shaft within a working surface may include a ram accelerator assembly for accelerating a projectile into geologic material to weaken a region of the geologic material. A cutting tool may then be used to remove the weakened material. A collection assembly may be used to move debris away from the working surface while the projectile and cutting operations are performed to enable generally continuous use of the system. The number of projectiles that are accelerated and the rate at which projectiles are used may be controlled based on characteristics of the geologic material and the rate at which created debris may be removed.

One or more ram accelerator devices may be used to form one or more holes in geologic or other material. These holes may be used for drilling, tunnel boring, excavation, and so forth. The ram accelerator devices propel projectiles which are accelerated by combustion of one or more combustible gasses in a ram effect to reach velocities exceeding 500 meters per second.

A hole in geologic material, such as a wellbore, may be extended by impacting the working face of the hole with high velocity projectiles. A tube may be placed within the hole, and the lower end of the tube may be sealed to prevent ingress of material from the hole into the tube. A projectile may be accelerated through the tube, such as by igniting a combustible gas mixture to impart a force to the projectile. The impact of the projectile may extend the hole. In some cases, accelerated projectiles may be used in conjunction with a drill bit to drill a wellbore or other type of hole.

One or more ram accelerator devices may be used to form one or more holes in geologic or other material. These holes may be used for drilling, tunnel boring, excavation, and so forth. The ram accelerator devices propel projectiles which are accelerated by combustion of one or more combustible gasses in a ram effect to reach velocities exceeding 500 meters per second.