US 4,228,508 A · Automatic longwall mining system and method

Abstract

A power loader having upper and lower cutting drums travels along the length of a face conveyor. Seam-top and seam-bottom sensors mounted on the power loader sense the heights of the true seam-top and seam-bottom. The data produced by these sensors during machine travel is not used to directly change the heights of the upper and lower cutters in the manner of an immediate-response automatic interface-follower system. Instead, to prevent the system from reacting and/or overreacting to changes in interface conditions, including changes which are physically insigificant and/or which, if fully reacted to, would exceed the floor and roof-negotiating abilities of the equipment, the system follows a preestablished interface-shape program. However, the true seam-top and seam-bottom height data from the sensors is fed into the process-control computer of the system, and used to modify and update the stored interface-shape program in a gradual ongoing manner. The computer ascertains, relative to predetermined criteria relating to the permissible rate of interface-shape program change in going from one power-loader working trip to the next, how much of the ascertained error in the interface-shape program can safely be eliminated per working trip for the successive working trips of the machine. And the erroneous intervals of the stored interface-shape program are then changed by such amounts during successive working trips, to gradually and stepwise dose out over a plurality of working trips the corrective reduction in the amount of the error exhibited by the stored interface-shape program.

Claims12

Dependent claims

An improved method of controlling the operation of a longwall excavating machine which during a working trip works the face of a longwall excavation, particularly a power loader mounted for movement along the length of a face conveyor, or the like, the method being of the type wherein a coal-seam interface-shape program is stored in a programmable control arrangement operative for causing the excavating machine to excavate in accordance with the stored program during at least one working trip,

the improvement comprising:
using coal-seam interface sensor means to generate data indicative of true coal-seam interface-shape conditions;
feeding said data into the programmable control arrangement and causing the latter to compare said data against the stored coal-seam interface-shape program and ascertain the error in the stored coal-seam interface-shape program relative to the true coal-seam interface conditions detected by the sensor means;
and causing the programmable control arrangement to automatically and gradually modify the stored coal-seam interface-shape program in ongoing depedence upon the ascertained error to thereby automatically and continually update the stored coal-seam interface-shape program followed by the excavating machine.

1 more element

An improved longwall mining system, of the type comprising a longwall excavating machine which during a working trip works the face of a longwall excavation, particularly a power loader mounted for movement along the length of a face conveyor, the system furthermore being of the type including programmable control means operative for storing a coal-seam interface-shape program and causing the excavating machine to excavate in accordance with the program during at least one working trip,

the improvement comprising:
coal-seam interface sensor means on the excavating machine operative for generating data indicative of true coal-seam interface-shape conditions as the excavating machine performs a working trip and feeding said data into the programmable control means,
the programmable control means comprising means receiving said data, comparing said data against the stored interface-shape program, and ascertaining the error in the stored interface-shape program relative to the true coal-seam interface conditions detected by the sensor means, and means operative for automatically and gradually modifying the stored coal-seam interface-shape program in ongoing dependence upon the ascertained error to thereby automatically and continually update the stored coal-seam interface shape program followed by the excavating machine.

Dependencies are inferred from the claim text.

Automatic longwall mining system and method

Life of this patent

Automatic longwall mining system and method

Life of this patent

Abstract

Claims12