There are many situations, where a tunnel or a cavity is needed underground. For all these works, one needs machines and the system of organization of the work: a Digger.


The System

    There are three areas in the System:

·        Digging Area, where the Digging Machine works,

·        Digging Support Area, where all needed materials and supplies are prepared and dirt from digging is disposed,

·        Ready Part of the Tunnel, trough which materials, energy, fresh air, etc. are transported to the Digging Machine and excavated dirt is removed to Digging Support Area for disposal.

Ready Part of the Tunnel should be fully reinforced, including its floor, and should be prepared for use during digging operations. On its ceiling should be: lighting fixtures, communication equipment, and cables supporting lighting and communication. This should be operational all the way between the Dig Support Area and the Digging Machine.

Carts should move materials from the Digging Support Area to the Digging Machine and dirt from the Digging Machine to the Digging Support Area. They should be used also to move other supplies to the Digging Area, like compressed air in cylinders, and should be used by Digging Machine operators to move back-and-force through the Ready Part of the Tunnel.


Power Supply

    Electricity is a best way to transfer energy underground. Hence we need to transfer electricity to the Digging Machine from the Dig Support Area via a cable. This Power Cable should be mounted on the ceiling of the emerging tunnel as the Digging Machine extends the Tunnel. All “portions” of this Power Cable should have ready Connectors facilitating their chaining into one reliable cable.

New portions of this cable should be delivered to the Digging Machine on a reel. The cable is unrolled from the reel, as the machine move into the dig.

Carts should have electric batteries, which should be topped-up at both ends of their travel – at the Dig Support Area and at the Digging Machine.



It is undesirable to use electric motors in this System, because they could cause sparks, which are dangerous in environment potentially full of combustible dust. Each machine should be driven by a hydraulic motor, fed through hydraulic transmission (see Hydraulic Transmission on this site). The hydraulic fluid should be pumped by a pump, run by a reciprocating electric motor (see “Pump” on this site). This electric motor should be encapsulated inside the pump to avoid escaping sparks, and this is easy to do with the pump of this design.

Each wheel of the Digging Machine and of a Cart should have dedicated hydraulic motor. Hydraulic motors are reliable and inexpensive.



    At any moment, when the Digging Machine works, at least two Carts are needed to support digging: one to hold cavity reinforcement and other materials, and the other to collect excavated dirt.

When a dirt collecting Cart is full, it should carry the dirt out.

From the other Cart, from which cavity reinforcement material have been partially used up, the rest of material should be transferred onto the Digging Machine. After that, the Cart should be used to collect excavated dirt.

    The first Cart should move dirt outside, where it should be unloaded. After that, it should be loaded with cavity reinforcement and other material and should return to the Digging Machine.

    Obviously, width of the tunnel, Digging Machine and Carts should be coordinated that two Carts could follow the Digging Machine right behind it.

    When the distance from the Digging Machine to the Digging Support Area becomes large, instead of one Cart, a train of a few Carts should be used, to avoid situations, where a Digging Machine has to wait for arrival of a Cart.

    Carts should be controlled remotely, they should have rubberized wheels – the floor of the tunnel should be “paved” with cavity reinforcement materials and wheels of Carts should not damage it.   


Digging Machine

    Digging Machine is used for:

·        digging,

·        dirt transfer from the front of the machine to its back

·        loading a Cart,

·        storage of cavity reinforcing material,

·        reinforcing the cavity of the tunnel,

·        installation of power, lighting and communication cables on the ceiling of the tunnel.

    It should a few types of manipulators for:

·        digging (with digging “claws”),

·        support of digging (guiding the dirt removal, drilling, preparing minor explosions, etc.),

·        transfer of material, installation of cables, etc.

·        installation of the cavity reinforcement material.

Manipulators should be supported with the Remote Viewing System (see “Remote Viewing” on this site).

Illumination of the work area should be controlled by the Remote Viewing System.

    On the bottom the Digging Machine should be a “tunnel” with a transporter in it. The transporter should reach above the Cart, where the dirt has to be collected.

    The Digging Machine should move on wheels, preferably rubberized. As it was mentioned above, each wheel has to have a dedicated hydraulic motor.

    To support digging, the Digging Machine should have special “legs”: on top, bottom and sides of it. These legs should extend and press against the ceiling, floor and sides of the tunnel.


Operators, Fresh Air and the Cabin

    At least two operators are needed to control digging, cavity reinforcement and transfer of material between the Digging Machine and Carts.

They need supply of fresh air and a Cabin, protecting them from debris and dirt. With the Remote Viewing System in place, the Cabin does not need and should not have windows. Operators should see and hear, what goes on around the machine, using external cameras and microphones and internal screens and speakers.

    Compressed air should be supplied in cylinders and empty cylinders should be returned to the Digging Support Area using Carts.


Digging a Large Cavity

    To dig a large cavity, a initial tunnel should be made to the top layer of this emerging cavity. Then the Digging Machine removes this top layer path-by-path, where each path starts at the end of this initial tunnel. All support operations are the same as during digging of a tunnel. Cavity reinforcement – materials and methods, are obviously different from tunnel reinforcement, though.

    When the top layer of emerging cavity is removed and reinforced, the initial tunnel is made deeper, that it ends at the second layer of the cavity. Then a second layer of the emerging cavity is removed and so on.

Alexander Liss 5/20/2020