GMSA offers a complete range of heat-treated grinding media solutions: From forged steel to a range of cast high-chromium alloys, GMSA can offer the right product to suit different customer applications.

Technical Support

GMSA holds a technology license with Magotteaux, a leader in the development and design of high chrome grinding media. This partnership ensures that our customers receive world class technical support and access to cutting edge high chrome grinding media technology. We offer help and guidance to customers, from selecting the best wear-resistant alloy, to assessing its impact on grinding chemistry and the subsequent beneficiation process.

Stages of Mill Development


  • Audits
    • Understanding of production, maintenance and commercial targets (e.g. recovery, wear rates);
    • Historical data collection and circuit surveys
  • Analyses
    • Interaction between all operational parameters (e.g. Ore hardness, mill size)
  • Recommendations
    • Proposal of equipment parts and or ‘tune up’ equipment running parameters;
    • Advice on mill specifications prior to mine development
  • Product development and Improvement
    • Continued optimization of ball chemistry to enhance ball grinding efficiency


  • Customer Services
    • On site sales engineers to provide technical support
  • Installation and Supervision
    • Advice on optimal equipment set up and configuration
    • Provision of proprietary technology such as Magoload®, automated ball loading technology, and Sensomag®, on-line filling sensor, which can be linked in order to control grinding media addition to maintain a pre-defined filling degree.
  • Contract Management
    • Assistance and advice on delivery logistics

Performance Evaluation

  • Performance Follow- up
    • On line key data collection through real time mill monitoring tools
    • Feedback visit exports to customers
  • Solution Optimizing
    • Redefining technical segmentation of applications.
  • Equipment availability
    • Improve, correct, react and proactively intervene to keep equipment performance at optimum levels

Heat-Treated High Chrome Balls

The High Chrome Ball Plant operates three production lines, all situated at our Germiston site. Balls are produced in a range of different chemistries, with chrome contents ranging from 11% to 32% and sizes ranging from 17mm to 100mm. Different heat-treatment cycles are used to impart specific metallurgical properties depending on the intended application. Whether the predominant wear mechanism is abrasion, corrosion or impact, GMSA can offer a product to suit.

Heat-Treated High Chrome Balls Production Cycle

  1. Scrap Processing and Charging;
  2. EAF Operation;
  3. Spout Pouring;
  4. Shaker, Breaker, Sorting and Heat Treatment;
  5. Mill Test;
  6. Despatch.
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Heat-Treated Forged Steel Balls

Round steel bars used for the production of forged steel balls are sourced from an integrated steelworks on site.

All GMSA forged media are manufactured to international quality standards and the processes include a quench & temper stage for improved hardness & toughness, providing for excellent impact and wear performance.

The Forged Ball Plant operates three production lines, with all products being manufactured to international standards.

Smaller, roll formed balls from 38mm-76mm are manufactured on our state of the art roll-forming machine and are fully heat-treated. Larger balls from 90mm to 125mm are produced by an upset-forge process with in-line tempering. The processes all include the heat treatment cycle for improved toughness and hardness.

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Mining Industry Experience

GMSA is the leading supplier of the grinding media requirements for the Southern African mineral processing industries, (gold, platinum, base metals, cement and power generation) with exports to many African countries and more recently to Australia. The GMSA production facility has been producing and supplying grinding media for more than 70 years.