3788 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
and availability compared to RMDs. This leads to energy
savings and increased uptime.
The largest GMDs in operation nowadays are the well-
established 40 ft, 28 MW SAG and 28 ft, 22 MW ball
mills. Metso and ABB also manufactured the first and only
42 ft, 28 MW mill and GMD, but to date no manufac-
turer ventured above this dimension. Over the last decade
these GMDs have reliably accumulated thousands of run-
ning hours. This paper investigated and proposed design
solutions for GMDs for SAG mills up to 44 ft, 35 MW
and ball mills up to 32 ft, 30 MW. The approach is to
minimize the risks by, on one hand building on the well
proven design of the largest GMDs in operation, and on
the other hand by using state-of-the-art simulation tools,
validated by tests and measurements. The impact of the
higher torque, dimensions and altitude on the electrical,
thermal and mechanical design was systematically investi-
gated. After several computational analysis and tests Metso
and ABB can confidently state that the new generation of
large GMDs is ready to be manufactured.
REFERENCES
Bordi, D., &Green, N. 2023. The Next Generation of
Very Large Grinding Mills, Paper presented at the SAG
conference 2023. Vancouver, British Columbia.
Gaunt, J.D., Lange, J, Titley, E., and Lu, T. 2014. 2014
Technical Report On The Pebble Project, Southwest
Alaska, USA. NI43-101 report of Northern Dynasty
Minerals Ltd. Retrieved from sedar.com on December
22, 2023.
Meimaris, C., Lai, B., Price, B. F., &Manchanda, S. 2006.
How big is big? Revisited. Paper presented at SAG
Conference 2006 (Vol. 2, 11–25). Vancouver, British
Columbia.
Orser T., Svalbonas V. and van de Vijfeijken M. 2011,
Conga: the world’s first 42 foot diameter 28 MW gear-
less mill, SAG 2011 conference, Vancouver, British
Columbia, Canada.
Riezinger, F. M., Knecht, J., Patzelt, N., &Errath, R. A.
2001. How big is big—exploring today’s limits of
SAG and ball mill technology. Paper presented at SAG
Conference 2001 (Vol. 2, 25–43). Vancouver, British
Columbia.
Figure 12. Mill-Motor interface analysis
and availability compared to RMDs. This leads to energy
savings and increased uptime.
The largest GMDs in operation nowadays are the well-
established 40 ft, 28 MW SAG and 28 ft, 22 MW ball
mills. Metso and ABB also manufactured the first and only
42 ft, 28 MW mill and GMD, but to date no manufac-
turer ventured above this dimension. Over the last decade
these GMDs have reliably accumulated thousands of run-
ning hours. This paper investigated and proposed design
solutions for GMDs for SAG mills up to 44 ft, 35 MW
and ball mills up to 32 ft, 30 MW. The approach is to
minimize the risks by, on one hand building on the well
proven design of the largest GMDs in operation, and on
the other hand by using state-of-the-art simulation tools,
validated by tests and measurements. The impact of the
higher torque, dimensions and altitude on the electrical,
thermal and mechanical design was systematically investi-
gated. After several computational analysis and tests Metso
and ABB can confidently state that the new generation of
large GMDs is ready to be manufactured.
REFERENCES
Bordi, D., &Green, N. 2023. The Next Generation of
Very Large Grinding Mills, Paper presented at the SAG
conference 2023. Vancouver, British Columbia.
Gaunt, J.D., Lange, J, Titley, E., and Lu, T. 2014. 2014
Technical Report On The Pebble Project, Southwest
Alaska, USA. NI43-101 report of Northern Dynasty
Minerals Ltd. Retrieved from sedar.com on December
22, 2023.
Meimaris, C., Lai, B., Price, B. F., &Manchanda, S. 2006.
How big is big? Revisited. Paper presented at SAG
Conference 2006 (Vol. 2, 11–25). Vancouver, British
Columbia.
Orser T., Svalbonas V. and van de Vijfeijken M. 2011,
Conga: the world’s first 42 foot diameter 28 MW gear-
less mill, SAG 2011 conference, Vancouver, British
Columbia, Canada.
Riezinger, F. M., Knecht, J., Patzelt, N., &Errath, R. A.
2001. How big is big—exploring today’s limits of
SAG and ball mill technology. Paper presented at SAG
Conference 2001 (Vol. 2, 25–43). Vancouver, British
Columbia.
Figure 12. Mill-Motor interface analysis