Mining or in situ disintegration of hard material – Processes
Patent
1992-11-06
1994-08-23
Bagnell, David J.
Mining or in situ disintegration of hard material
Processes
299 33, 299 71, E21C 2516, E21D 910
Patent
active
053401999
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for excavating drifts, tunnels, stopes, caverns and the like with tools such as disc cutters, operating in an undercutting manner on a rock face, and a machine for performing such excavation.
2. Description of the Prior Art
Undercutting disc cutters working from a pilot bore-hole or opening are known as an effective cutting system, since in such a case, it is not the high compressive strength of the rock which must be overcome, but rather only its low tensile strength. A tunnelling machine with a rotary head is known (DE 31 40 707 A1), which has a pilot borer located on the front of the head working in a conventional manner (i.e. using a conventional drilling head) and spaced behind it in the axial direction, a plurality of tool supports are provided which are formed as radially pivotable arms. Disc cutters mounted on these arms start from a centrally located pilot hole in order to cut the rock in an undercutting manner with a radial pivoting-out motion of the arms. To cut the pilot hole with a relatively large diameter using a conventional drilling head requires a great deal of effort and is difficult to achieve concurrently with the operation of the disc cutters working in the undercutting mode. It is also considered disadvantageous that the pilot bore-hole drilling process requires high thrust.
In another known tunnelling machine (DE 87 17 189 U1), two pivotable supporting arms equipped with disc cutters are mounted parallel to one another on a rotary head in such a manner that they are located on either side of a diameter line of the head. The pivot points of the supporting arms are located on the periphery of the head, in such a manner that the supporting arms face one another. Instead of drilling a pilot hole, in this case each of the two disc cutters makes a start on the rock at a point lying on the far side of the central line which corresponds to the axis of rotation of the head, with respect to the pivot point of the associated supporting arm, and then moves along the path of pivoting of the arm beyond this central line and continues out to the perimeter of the opening. This means that each disc cutter is subject to very different conditions during the course of the pivoting movement of its supporting arm. In particular, each disc cutter starts a small distance from the central line, this distance decreasing until the central line has been crossed. Following this, the disc cutter is still operating in the vicinity of the central cutting area. As will be explained later, this is inefficient. Moreover, the machine is restricted to the use of only two disc cutters.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is to provide a method of excavating drifts, tunnels, stopes, caverns or the like using the undercutting principle, but without the necessity for a predrilled pilot opening, produced separately using a conventional drilling head. According to this invention an effective cutting of the rock face is possible under favourable conditions for the tools using solely the undercutting principle. Furthermore, a larger number of tools than two can be used. In addition to the method, the invention is intended to create a machine which is particularly suitable for carrying out the method and with which drifts, tunnels or the like can be excavated with favourable operating conditions for the tools. The invention also aims to provide, in particular, an advantageous embodiment of such a machine. Further advantages of this invention are discussed in the description given below.
The invention proposes that with at least one tool mounted on a pivotable tool arm which itself is mounted on a rotating head of the machine, a central region of the rock face is cut radially from the outside inwards by pivoting the tool arm, and with at least one other tool mounted on at least one other pivotable tool arm carrying said tool, an outer region surrounding the central region of the rock face is cut radially fr
REFERENCES:
patent: 1806792 (1931-05-01), Degenhardt et al.
patent: 3695717 (1972-10-01), Birrer
patent: 3814481 (1974-06-01), Montacie
patent: 4248481 (1981-02-01), Stoltefuss
patent: 4805963 (1989-02-01), Kogler et al.
Handbook of Mining and Tunnelling Machinery by B. Stock, pp. 285-293, 1982.
Hamburger Hermann
Piefenbrink Wilfried
Weber Walter
Bagnell David J.
HDRK Mining Research Limited
Steen Edward A.
Wirth Maschinen-Und Bohrgerate-Fabrik GmbH
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