The invention relates generally to mining valuable mineral and/or metal deposits and particularly to mining machines and methods for continuous or semi-continuous mining or such deposits.
Annually, underground mining of valuable materials is the cause of numerous injuries to and deaths of mine personnel. Governments worldwide have enacted restrictive and wide-ranging regulations to protect the safety of mine personnel. The resulting measures required to comply with the regulations have been a contributing cause of significant increases in underground mining costs. Further increases in mining costs are attributable to global increases in labor costs generally. Increases in mining costs have caused numerous low grade deposits to be uneconomic to mine and therefore caused high rates of inflation in consumer products.
To reduce mining costs and provide for increased personnel safety, a vast amount of research has been performed to develop a mining machine that can excavate materials continuously and remotely. Although success has been realized in developing machines to mine materials continuously in soft deposits, such as coal, soda ash, talc, and other sedimentary materials, there continue to be problems in developing a machine to mine materials continuously in hard deposits, such as igneous and metamorphic materials. As used herein, “soft rock” refers to in situ material having an unconfined compressive strength of no more than about 100 MPa (14,000 psi) and a tensile strength of no more than about 13.0 MPa (2,383 psi) while “hard rock” refers to in situ material having an unconfined compressive strength of at least about 150 MPa (21,750 psi) and a tensile strength of at least about 15 MPa (2,750 psi). Ongoing obstacles to developing a commercially acceptable continuous mining machine for hard materials include the difficulties of balancing machine weight, size, and power consumption against the need to impart sufficient force to the cutting device to cut rock effectively while substantially minimizing dilution, maintaining machine capital and operating costs at acceptable levels, and designing a machine having a high level of operator safety.
For example, a common excavator design for excavating hard rock is an articulated excavator having a rotating boom manipulated by thrust cylinders and an unpowered cutting head having passive cutting devices, such as a box-type cutter using discs or button cutters. Such excavators typically only impart 25% of the available power into actual cutting of the rock and can be highly inefficient. Unproductive parts of the cutting cycle are substantial. For example, repositioning of the excavator requires some actuators to be extended and others retracted until a desired position is reached at which point the extended actuators are retracted and the retracted actuators extended. During excavator repositioning, no excavation occurs.
These and other needs are addressed by the various embodiments and configurations of the present invention. The present invention is generally directed to the use of a powered cutter head and/or elongated support member (such as a cable or wire rope) in the excavation of various materials, particularly hard materials.
In a first embodiment of the present invention, an excavation method is provided that includes the steps:
In a second embodiment, an excavation is provided that includes the steps:
The use of a powered, rotating cutting head, particularly one having a number of small discs, that cuts the advancing excavation face from the side of the cutting head can provide advantages relative to conventional excavators using box-type cutting heads. At any one time, only a portion of the discs are in contact with the rock and cutting; the remainder are out of contact with the rock and not cutting. The required cutting forces are typically drastically reduced compared to the box-type cutting head, in which all of the cutters are in continuous contact with the excavation face during cutting. Moreover, an excavator using a powered cutting head to cut rock on only one side of the cutting head generally has only to push hard in one direction. An excavator using a box-type cutting head, however, generally must push hard in two directions and must travel much farther than the power cutting head. Consequently, an excavator using a powered cutting head can be much smaller than an excavator using a box-type cutting head. By way of illustration, a typical box-type cutting head excavator must handle about 300,000 pounds of thrust so the bearings are quite large, thereby enlarging substantially the overall machine size. In comparison, an excavator having a powered cutting head need only handle small thrust loads so its bearings and the entire machine can be made much smaller. A powered cutting head commonly requires a cutting force of less than about 50,000 lbs and more typically ranging from about 30,000 to about 40,000 lbs.
In a third embodiment, a mobile deployment frame for an excavator is provided that includes:
The deployment frame can not only perform excavator support during excavation-but also assist the excavator in self-collaring at the start of an excavation cycle. The area defined by the first and second arms and the central body member is large enough to receive the excavator.
In a fourth embodiment, an excavator is provided that includes:
The position of the cutting head relative to the body is fixed relative to a direction of travel of the excavator while excavating.
The excavator can move continuously throughout the cycle of excavating a side of the block, thereby obviating the need for repositioning the excavator at a number of discrete locations and locking the excavator into a stationary position before the excavation cycle can be commenced. Accordingly, unproductive parts of the cutting cycle are substantially minimized.
The various excavators discussed above are readily adaptable to remotely controlled operation to provide increased personnel safety.
These and other advantages will be apparent from the disclosure of the invention(s) contained herein.
The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.
As used herein, “at least one,” “one or more,” and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
The various excavators of the present invention are particularly suited for mining steeply dipping hard or high strength mineral deposits (having a dip of about 35° or more and more typically of about 45° or more) having thicknesses from several inches to several feet. Preferably, the excavations used are similar to those discussed in U.S. Pat. No. 6,857,706, in which the deposit is divided into a series of blocks. Each block is delineated using multiple excavations, such as tunnels, headings, drifts, inclines, declines, etc., positioned above and below each block of the deposit (and typically in the plane of (and generally parallel to the strike of) the deposit) and multiple excavations, such as shafts, stopes, winzes, etc., positioned on either side of the block. As used herein, the “strike” of a deposit is the bearing of a horizontal line on the surface of the deposit, and the “dip” is the direction and angle of a deposit's inclination, measured from a horizontal plane, perpendicular to the strike. Although the excavation method is described with specific reference to steeply dipping deposits, it is to be understood that the excavators described herein can be used for any mining method for excavating a deposit having any strike or dip, whether horizontally or vertically disposed, and being hard or soft rock.
A first excavation system will now be discussed with reference to
The excavator 400 can self-collar to initiate excavation of a next segment. This capability is shown by
The mobile deployment system 100 will now be described in more detail with reference to
An alternative configuration of the system 100 is shown in
The excavator 400 will now be discussed with reference to
The manifold 800 contains the actuators 416, 418, 420, and 422, hydraulic components needed to support the actuators and thrust cylinders in the stationary frame (discussed below), excavator electronics, and control system for remotely controlled operation. Additionally, an umbilical (not shown) extending from the system 100 to the excavator 400 is typically connected to the manifold 800. The umbilical contains conduits for providing and returning pressurized hydraulic fluid and water and conductive members for providing electrical power and telemetry. The control system can be any suitable command and control logic such as that discussed in U.S. Patent application Ser. No. 10/688,216, filed Oct. 16, 2003, entitled “Automated Excavation Machine.” The support member 408 is attached to a rear attachment assembly 450 having an attachment member 454 rotatably engaging mounting members 458a,b.
The sliding cutter assembly 808 will be described with reference to
The cutter drive assembly 1012 will be discussed with reference to
Finally, the stationary frame 804 is discussed with reference to
The deployment frame 100 may be powered so as to be able to move in the excavation in which it is positioned and thereby move the excavator. Alternatively, the deployment frame 100 may be unpowered and towed by a powered vehicle or winch and cable assembly to effect movement of the excavator.
The operation of the excavator 400 will now be described with reference to
When the cutting head 428 has been fully displaced laterally, the actuators 416a,b, 418a,b, 420a,b, and 422a,b are retracted and the excavator 400 moved by the support members 404 and 408 to a next position and the sequence repeated. As can be seen from this description, the mobile deployment system 100 can provide both vertical thrust and position control.
Unlike the excavator of the prior embodiment which relies on hydraulic cylinders to provide a substantial portion of the required additional cutting forces to the cutting head 440, the excavator of this embodiment relies on the front support member 2040 to provide a substantial part of the required additional cutting forces. The use of hydraulic cylinders to provide a substantial part of the required additional cutting forces can require larger excavator sizes and weights to counteract the forces imparted by the cylinders. Using one or more winches and flexible, high strength support members, in contrast, coupled with a motorized, rotating cutting head can provide substantial reductions in the excavator size and weight required for acceptable excavation rates.
In operation, the excavator 2000 is positioned in a desired position by manipulation of the mobile deployment system 100 and the first and second winches. To accommodate the unique design of the excavator 2000, the positions of the support members are reversed relative to the positions shown in
When in the desired position, the cutting head is rotated and upward force is applied to the boom by the support member 2044. The boom rotates about the forward actuators 2016a,b to form an arcuate cut 2060. The radius of the cut 2060 is, of course, the length of the boom and cutting head 440 measured from the axis of rotation of the boom. When the cutting head is passed through the excavation face as shown by the dotted lines, the actuators of the excavator are retracted and disengaged from the hanging wall and footwall and the excavator moved using the rear support members 2044a,b, to a next desired position to initiate a next cutting sequence.
As will be appreciated, the orientation of the “cut” or excavation pass by the cutting head can be controlled or “steered” by differentially extending the various actuators in the body. The plane of the excavation pass is generally parallel to the plane of the upper and lower plates 2050a,b of the body 2004 because the boom 2008 has freedom of movement only in the plane of the page of
A further embodiment of an excavator is shown in
Referring to
A number of variations and modifications of the invention can be used. It would be possible to provide for some features of the invention without providing others.
For example in one alternative embodiment, the tracks 2404a-h are steerable (or rotatable in the plane of the page of
In another embodiment, the powered winch is replaced by a powered vehicle that tows the excavator during excavation. This embodiment is particularly attractive for horizontal or relatively flat-lying deposits.
In another embodiment, the thrust force is provided collectively both internally, such as by one or more thrust cylinders, and externally, such as by a support member and winch.
The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.
The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.
Moreover, though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.
The present application claims the benefits, under 35 U.S.C. §119(e), of U.S. Provisional Application Ser. No. 60/565,250, filed Apr. 23, 2004, entitled “Mining Method and Apparatus,” and Ser. No. 60/633,158, filed Dec. 3, 2004, entitled “Rock Cutting Method and Apparatus,” each of which is incorporated herein by this reference. Cross reference is made to U.S. patent application Ser. No. 10/688,216, filed Oct. 16, 2003, entitled “Automated Excavation Machine,” and Ser. No. 10/309,237, filed Dec. 4, 2002, entitled “Mining Method for Steeply Dipping Ore Bodies” (now issued as U.S. Pat. No. 6,857,706), each of which is incorporated herein by this reference.
Number | Date | Country | |
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60565250 | Apr 2004 | US | |
60633158 | Dec 2004 | US |