Dec '07/Jan '08

Innovation Page

Reducing the cost of wear in mining and mineral processing

By R. Llewellyn and G. Winkel

Erosion and corrosion — two words that represent a significant cost to many mining operations. This month we profile a collaborative effort by mining firms to address wear in our industry.

The initiative under review is an industry-sponsored Mining Wear Materials Program at the National Research Council Canada’s Institute in Vancouver. In mining and mineral processing there are numerous permutations of wear mechanisms, often involving corrosion in synergistic attack, that are encountered in the different operations and processes involved. This situation necessitates the identification and application of a multiplicity of materials, designs and process considerations to prevent or minimize attack. With respect to wear materials, they range from soft elastomers and polymers to extremely hard engineering ceramics and cermets, and ultimately to diamond-like surface layers.

History

The collaborative effort between the National Research Council (NRC) and industry was initiated in 1996 by Syncrude, which had its own wear materials research program in place, but envisioned that larger gains and faster progress could be achieved by a more concerted collaborative effort. This work has expanded out to include other oil sands and hard rock mining firms. The current participating mining firms include Quebec Cartier Mining, Xstrata, Alcoa, Albian Sands Energy, Canadian Natural Resources, Fort Hills Energy LP, Suncor and Syncrude. The initiative also enjoys strong participation by a core group of industry wear material supply members with proven records of success in developing and manufacturing state-of-the-art wear protection technology for mining, which in turn complements the mining user members’ group. The consortium now has a total industrial membership of 17 companies and is very ably supported by other research providers such as the University of Alberta, University of British Columbia and the Alberta Research Council.

Wear materials program

The main objectives set for the Mining Wear Materials Program include:

  • Identifying the most resistant/protective options for specific wear modes. 
  • Characterizing damage mechanisms and correlating performance with condition, microstructure, and constitution.
  • Providing a comprehensive database of wear properties to help in selecting optimum materials for critical service applications.
  • Supporting the development of improved wear materials and protection systems.
  • Addressing chronic wear problems and analyzing failures of wear components.
  • Improving knowledge among mining companies and suppliers of the mechanisms and influences on attack and of the relative properties of wear materials.

Evaluation capabilities

The optimization of wear performance requires sophisticated and standardized techniques. Wear determinations are made at NRC using a range of testers that simulate critical attack mechanisms occurring in mining. Some of the most important systems are:

  • A rolling contact abrasion tester for assessing shovel and tractor undercarriage component steels and also for evaluating lubricants.
  • Low-stress (ASTM G65) and high stress dry abrasion and slurry abrasion (ASTM G105) testers for a range of sliding wear situations (e.g. shovel linings, hoppers, truck boxes, ground engaging tools, drill parts, piping).
  • Gouging abrasion (ASTM G81) testing for crushers, sizers and breakers. 
  • Reciprocating stroke, room and high- temperature abrasion tests for evaluating materials for smelting and for fretting wear.
  • Slurry jet and scouring (Coriolis) erosion and erosion/corrosion testers that reproduce conditions present in slurry pumps, piping, nozzles, valves and separators.
  • Air jet erosion (ASTM G76) for materials for pneumatic transportation of hard solids.

Benefits

This collaborative wear materials research effort has produced real gains for the mining industry. Some very significant improvements in the battle to control wear and improve performance follow.

  • The replacement of austenitic manganese steels by low alloy steels in shovel buckets in hard rock mining has resulted in improved performance, reduced maintenance and, very critically, healthier working environments during welding operations. 
  • The determination of causes for chronic failures in shovel bucket lips and shovel track pads has resulted in increased reliability and equipment availability in hard rock situations.
  • An extensive wear properties database has been compiled that allows group members to make comparisons between materials and to achieve more informed selections.
  • Data obtained in the program on established and newly developed products has been used during the design stages for new plants and in expansion projects.
  • Assessments of the relative abrasivity and erosivity of solids in mining and related transportation streams have explained service behaviour and allowed action to be taken to minimize adverse conditions.
  • The selective introduction of sintered carbide components has resulted in major increases in service life and plant up-time in froth treatment processing.
  • The use of a laminated wear plate for a novel breaker plate design in oil sands ore preparation is greatly reducing replacement frequency and improving plant availability and total production throughput.

The consortium clearly demonstrates another collaborative research effort that is returning value to the mining industry. For more information on this work please contact Rees Llewellyn, MWM Group Leader, National Research Council Canada, at rees.llewellyn@nrc.gc.ca or by phone at 604.221.3072.


Rees Llewellyn is MWM group leader, National Research Council, Canada.
Gord Winkel is oil sands technology manager, Kearl Oil Sands Project, Imperial Oil Resources.

Post a comment

Comments

PDF Version