The copper industry is cyclical with the price determined by market forces (i.e. the balance between supply and demand for the metal.) The period of each cycle typically varies between 6 to 9 years. These cycles drive decision making for exploration, new project and mine development,mine closures, p...
23-Jan-2009
HPGR in series can be used to grind a large proportion of the feed to product size but efficiency reduces after the second pass.
.. Smaller-diameter HPGR rolls can increase the breakage of coarse particles in multi-pass circuits.
.. Smaller top-size, steeper size distribution
.. Coarsest particle...
22-Nov-2008
The energy efficiency of comminution processes is very low based on the energy required to generate new fracture surface area relative to the mechanical (strain) energy input. However, the maximum ideal limiting efficiency ELimit against which actual efficiencies may be compared is unknown. Therefor...
23-Oct-2008
This paper presents a new approach for determining the specific energy requirement of tumbling mill (grinding) circuits. It is used to demonstrate that there is no significant difference between the energy utilisation efficiency of any of the grinding circuits of the plants studied. Laboratory test...
23-Oct-2008
A cone crusher and a vertical shaft impact (VSI) crusher were operated in closed circuit to compare the performance of the two different crushing machines. The crushers were operated in closed circuit with a 9 mm final screen aperture size. A comparison of capacity, size reduction and power draw sho...
23-Sep-2008
•HPGR is seriously challenging SAG
•Driven by higher media and energy costs.
•Driven by ENERGY ACCOUNTING.
•Adopting Emergy might attract a strange mix of economists and energy scientists/engineers.
•The science of “emergy”is obscure and arcane, “It’s well-known, but only to a few!”
22-Sep-2008
The application of high pressure grinding rolls (HPGR) has been growing in the mining industry for the last 10 to 15 years. The major benefits supporting this trend are better energy efficiency, improved grinding capacity, and higher metal recovery in downstream processes such as heap leaching and f...
30-Aug-2008
The successful commissioning of the Cerro Verde project in Peru at the end of 2006 marked the culmination of the efforts of many in the industry over many years to have high pressure grinding roll technology recognized and accepted as a legitimate alternative to the conventional approach to large-sc...
30-May-2008
Metso Minerals Process Technology Asia-Pacific (MMPT-AP) has been working with many mining companies worldwide performing ‘Mine to Mill’ or Process Integration and Optimisation (PIO) studies. MMPT-AP has developed a proven methodology to improve the efficiency of the mine-mill interface and gain max...
28-Oct-2007
The resources sector has come to accept that the global quest for sustainable development is one of the key shapers of its future development and business success. While much uncertainty remains regarding the full ramifications of sustainable development, it is uncontested that preventive environmen...
23-Aug-2007
The current status of the modelling of comminution processes is assessed in light of its capabilities and weaknesses. The principles required for a major upgrade in modelling capability are proposed. The use of advanced computational techniques to provide detailed information on the mechanical envir...
23-Aug-2007
CEEC Technical Review Committee comments:
Another great paper reminding us that we already have the tools, data and knowledge to start implementing some energy saving strategies not only in grinding, but the all the way through to smelting. A holistic approach is taken and the question asked: Where...
23-Jul-2007
Since October 2003, the BHP Billiton Cannington mill has operated a grinding circuit consisting of an AG mill, pebble crusher and a Vertimill®which in this paper will be referred to as an AVC circuit. What is unique about this circuit is that it utilizes a Vertimill® for secondary grinding rather th...
01-Dec-2006
Oscillatory unstable behaviour in a SAG mill is characterised by the mill constantly cycling between an overload condition and recovery from that condition by a substantial reduction in feed rate tonnes. Such behaviour is commonplace with SAG mills and gives rise to a significant overall reduction i...
30-Nov-2006
Energy consumption and mineral recovery are among the most important factors affecting the mineral processing economy. There are a number of emerging new technologies which have proven to be more energy efficient for comminution, such as High Pressure Grinding Rolls (HPGR) and stirred milling techno...
23-Sep-2006
Johnson
Abstract
In achieving the necessary liberation for separation of valuable minerals from ores, metallurgists have traditionally selected from the competing options for size reduction devices by making decisions based on various types of costs. While these costs remain important in s...
23-Aug-2006
Abstract
Green, S and Smyth, E (2006) "Developing innovative technologies in support of sustainable minerals processing", presented at MCA Sustainable Development 2006 Conference: Operating for Enduring Value, Perth, Australia, 23-27 October 2006 (invited).
CEEC Technical Review Committee comment:...
22-Aug-2006
A finite difference quasi-static thermo-mechanical 2-D model of a theoretical 2-phase mineral is constructed. The aim is to simulate the thermal stresses generated and subsequent thermal damage when a rock particle is exposed to high electric field strength microwave energy. The influences of power...
23-Dec-2005
Significant improvements in design and wear abatement technology combined with escalating energy and steel media costs are making High Pressure Grinding Rolls (HPGR) increasingly attractive for applicable “hard rock” ore applications relative to SAG-Ball milling. In addition, HPGR offers significant...
30-Aug-2005
Extensive in-situ testings has shown that blast fragmentation influences the performance of downstream processes in a mine, and as a consequence, the profit of the whole operation can be greatly improved through optimised fragmentation. Other unit operations like excavation, crushing and grinding ca...
23-Jun-2005
International Journal of Mineral Processing 2004
Despite reservations of a number of researchers concerning the applicability of Bond's equation for relating specific energy to the size reduction of rocks, his approach has become an industry standard.
Data from a large number of pilot and full-s...
29-Mar-2005
The “functional performance equation for ball milling” was first presented in 1988. It has now been used successfully in a substantial number of mineral- processing plants. This powerful, yet simple, tool provides a new level of understanding of closed circuit grinding. It shows how grinding circuit...
02-Mar-2005
On behalf of the Mining Industry’s Task Force of the Canadian Industry Program for Energy Conservation (CIPEC), the Mining Association of Canada (MAC) retained the Competitive Analysis Centre Inc. to work with mining companies to establish energy benchmarks for underground bulk mining. Companies par...
04-Feb-2005
Metallurgical Plant Design and Operating Strategies 2004
Oceana Gold (New Zealand) Limited operates the Macraes Gold Mine near Dunedin on the South Island of New Zealand. The ore body is mineralogically complex and comparatively low grade requiring a series of unit processes and resulting in a re...
22-Oct-2004
Ore blending for process optimization is becoming an increasing factor for managing cost and productivity. Economic mining and processing a very low value ore in an extremely competitive market results in constant cost-cutting initiatives. The inherent conflict between the lowest possible mining cos...
02-Jan-2004
XXII International Mineral Processing Congress, Cape Town, South Africa
The introduction and subsequent ascendancy of autogenous and semi-autogenous milling for comminution circuits has undoubtedly lead to many economic advantages. From a process viewpoint, however, at least one downside has been...
23-Aug-2003
Public demand for the “Sustainable Development” and CO2 reduction will increase the pressure for more energy efficient comminution. To assess the avenues for reduction of energy required for comminution with already available technologies, modeling and simulations were undertaken using data from a n...
23-Sep-2002
This paper examines the design of comminution circuits and the issues that impact on comminution circuit efficiency.Circuit efficiency is discussed, principally from the perspective of power efficiency. However, operating efficiency, maintenance efficiency, capital expenditure and return on investme...
23-Sep-2002
The paper examines the current state of equipment and circuit design, with reference to Australian practice. Following a review of the changes in milling applications over the last fifteen years, developments in mill design are examined. Current issues include trunnion versus shell support; drive ty...
28-Jan-2002
30-Nov-2001
23-Nov-2001
This paper provides some basic guidelines for comminution circuit selection from a range of alternatives. Factors itemised in the decision making matrix include:
Project type and size
Ore characteristics and properties
Circuit cost considerations
Test work costs and impact on project schedule
S...
23-Nov-1999
Comminution 1998
This paper presents observations made during the conduct and analysis of eleven separate autogenous and semi-autogenous pilot plant trials. These trials were conducted using different ores for various projects over the past five years. The ores tested include relatively competent...
22-Nov-1998
The Julius Kruttschnitt Minerals Research Centre (JKMRC) has been involved in the study and modelling of industrial autogenous (ag) and semi-autogenous (sag) mills for over 20 years. Recent research at the JKMRC has developed a new ag/sag mill model which is based on charge dynamics. The model relat...
28-Nov-1996