Jim Dowling - Mining Engineer

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UNDERGROUND MINE PLANNING ANIMATIONS: A series of animations to illustrate some aspects of underground mine planning

 

In mine planning, subjects are three dimensional and, to completely understand what is happening, in a two dimensional text book, all these various orthographic projections are necessary:

  • Plan View - as seen looking vertically downwards.

  • Section - as seen looking horizontally.

  • Cross Section - as seen looking horizontally in the direction of the object’s longest horizontal dimension, if it has one, for instance the strike direction of a dipping vein.

  • Long, or Longitudinal, Section - as seen looking horizontally in a direction which is perpendicular to the direction of the object’s longest horizontal dimension.

  • Isometric View - looking at an object along a sight line typically less than 45°  to the length/width/height axes, to indicate its three dimensional shape.

  • Perspective View - an isometric view including size varying with distance.

  • Plane of Lode (POL) - a view where the sight line is tilted to show the subject as if it were horizontal and a true plan view, so the sight line is perpendicular to the plane of the object, usually a mineral vein. In this view of workings within a dipping vein (lode), dimensions up-dip and along strike are accurate and can be scaled off, as if it were a plan view of a horizontal subject.

It is also possible, with software, to add the variable time in an animation of a perspective view, to show how a mine plan develops from start of mining to exhaustion. The following videos are intended to clarify some of the planning concepts in my book.

The Man Engine video is a light hearted look at a historical technique used in some Cornish mines to raise and lower miners in shafts.

 

Shrinkage Stoping

A popular mining method for narrow, steeply dipping veins, This orebody outcrops at surface and dips at 70°. It has a strike length of 2000m, a vertical depth of 500m and is, on average, 2.0m wide (thick). It is assumed the natural geological variability in width and direction precludes the use of long holes due to excessive dilution and poor recovery.

Sublevel Open Stoping (SLOS)

A popular mining method for wider, steeply dipping veins, This orebody outcrops at surface and dips at 70°. It has a strike length of 2000m, a vertical depth of 500m and is 3.0m wide (thick). In this wider vein, dilution and recovery are now acceptable with long hole stoping. Long hole stoping is much more productive, and much cheaper, than shrinkage.

Room and Pillar Mining

Room and Pillar is used in most flat-dipping reserves which are thick enough to accommodate crawler-mounted and above all rubber-tyred equipment. It is ideally suited to sedimentary deposits such as coal and industrial minerals. It is also used in flat-dipping metalliferous deposits such as strata-bound lead/zinc. This reserve is horizontal, 420m deep and 3.0m thick. Boundaries are, as usual, variable, but extend to approximately 2.6 x 3.3km.

Man Engine

This consisted of timber rods with platforms which move up and down in the shaft, and fixed platforms at each extremity of movement. Miners traverse the often inclined shaft by stepping on and off moving platforms in the direction they need to go. Developed in the Hartz region in Germany, the technique arrived in Cornwall early in the 19th century. They proved to be generally safer, less arduous and quicker for miners to go to and from their place of work than the fixed ladders they replaced. Driven by water wheels or, most often, steam driven beam engines, they were replaced in the early 20th century by rope hoisting in vertical shafts.

 

 

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