Untersuchung der im Tagebau gewinnbaren Magnesitvorräte im Magnesitbergbau Hohentauern

Translated title of the contribution: An Investigation of the Open Pit Operation Recoverable Magnesite Reserves in the Hohentauern Magnesite Mine

Philipp Panny

Research output: ThesisMaster's Thesis

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Abstract

In the Styromag magnesite mine of Hohentauern the amount of magnesite which is recoverable is to be estimated. Do to so old geological maps, mining maps and drilling cores were available. Mining today is concentrated in the area between level I and level VI. In this region of the mine no mining has taken place in the past. The magnesite reserves were found to be estimated to 170.600 m³ (477.800 t). Under consideration of a good waste- to magnesite ratio, through the usage of various general inclinations, namely 35°, 40°, 45°, 50° and 55° and various mining limits a scenario was to be found were as much magnesite as possible could be mined economically. The results show that mining should take place under 45° general inclination up to the so called blue line along with the recovery of extra parts of the lying bench. This scenario is considered to be the most feasible and economically justifiable. In this case a total of 344.000 m³ of stone has to be mined. Of this 149.600 m³ (418.800 t) is magnesite and 194.400 m³ waste. Expressed in percent, 57% of the material mined is waste and 43% magnesite. Of all the magnesite reserves available in this area only 12% were not recovered. As expected the waste- to magnesite ratio is bad in the top regions of the mine and gets better as mining progresses downwards. If the general inclination were to be increased above 45° occupational safety and long – term stability can not be guaranteed. On the other hand if the general inclination decreases below 45°, mining becomes uneconomic. Recovering all magnesite reserves is not only uneconomic but also will lead to severe storage and disposal problems concerning the waste that would have to be mined. Below level VI underground mining has taken place in the past. As the company Styromag does not have any plans to start underground mining, level XIV had to be chosen as the lower mining limit. With the assumption of an ore recovery of 100% in the past 1,2 x 106 m³ (3,4 x 106 t) of magnesite were already stoped underground. The left over reserves of magnesite are 800.000 m³ (2,2 x 106 t). Large quantities of this cannot be mined economically in open pit mining operation. Depending on the safety distance chosen to the former underground stopes, different volumes of magnesite can be stoped economically. However a 5 m safety distance should not be undershot. With this safety distance a further 146.500 m³ (410.200 t) magnesite can be mined. The amount of waste in this case equals to 123.900 m³. Percentage wise thus 54% of the mined material is magnesite and only 46% waste. The existence of old backfilled stopes between level VI und level XIV as well as a few other workings above level VI and their effect on mining operations have to be taken into consideration when making an economic analysis.
Translated title of the contributionAn Investigation of the Open Pit Operation Recoverable Magnesite Reserves in the Hohentauern Magnesite Mine
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Wagner, Horst, Supervisor (internal)
Award date16 Dec 2016
Publication statusPublished - 2016

Bibliographical note

embargoed until 16-09-2021

Keywords

  • Magnesite
  • Recoverable reserves
  • Magnesitereserves
  • Hohentauern
  • quarrying
  • Open-Pit
  • Miningszenario
  • waste to ore ratio

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