Volume 9 Edition 3 2012 - The ASIA Miner

Primary Gyratory CrushersOEMs modify machines to make them safer and easier to maintainBy Steve Fiscor, Editor-in-ChiefPrimary gyratory crushers (PGs) r educe orefrom the pit to a consistent, manageable size.While most agree that PG design has changedvery little in the last 20 to 30 years, thoughtssurrounding PG installation have. Much of thatthinking has to do with declining or e grades.Many mines have to process more ore to retrievethe same amount of metals.Miners looking to process huge amountsof ore have to strike a balance between capacityand product size. Ideally, a single,massive PG could maintain a very high capacitywhile pr oviding a consistent smallproduct size. In the r eal world, however, atighter setting on the largest PGs meansless ore moves through the machine volumetrically.Adding multiple machines wouldmaintain the desired capacity levels, but italso increases capital and operating costs.Even though the principles r elated to PGshave not changed much, the way the minersinteract with the machines has. Obviouslycrushing mountains of rock takes its toll onthese machines. The original equipmentmanufacturers (OEMs) are striving to improvemaintenance methods. The safety of the peoplemaintaining these machines is paramount.The cost of maintenance, the dir ectexpense and the impact of downtime, is animportant consideration. Technology has advancedto the point where all of the machinesare delivered with software and control systemsthat allow them to interface with humansand other controls and machines.The OEMs have seen demand for PGs r e-bound from a lull in 2009. Business was briskprior to the global financial crisis and now demandis again returning to those 2007-2008levels and so are the lead times for the deliveryof new machines. The problem is the largecastings. A single piece weighs 50 to 100 tonsand only a few foundries can make these castings.All of the OEMs say to expect at least aone-year wait and, in some cases, that leadtime has now grown to 16 months or greater.Primary gyratory crushers reduce run-of-mine ore to a consistent size.Market DynamicsAs far as market shar e, Metso Minerals islargely viewed as the leader and it has thelargest installed base of PGs, but competitivecompanies have made significant inr oads.“Reports indicate that we had lost a littleground to some of our competitors in SouthAmerica,” said Ivan Pavlovic, director of miningcrusher capital projects, Metso Minerals.“When markets were taking off in places likePeru and Chile, the competition gained someground. We have since r eorganized with amerger and placed more emphasis on winningback the market share we lost.”Metso has received some large or ders recently.At times like these, ther e is a certainfrenzy to get these large pr oduction projectsonline quickly, Pavlovic explained. “Ther eseems to be a steady demand for all sizes ofPGs and we do very well in all parts of theworld,” Pavlovic said. “Lead times ar e manageable.The lead time for larger machines area little longer. Customers can r est assured,when their project comes online, the PG will beavailable. We’re looking at a year right now.”“For most customers, when it comes totrying to size these machines and determinethe settings, it has really become a shot in thedark because of the or e grade,” Pavlovicsaid. “The engineers r ely on modeling andsimulation and the models ar e often verygood, but they do not always accurately predictgrades and particle distribution.“For mines processing large quantities oflow-grade material, the semi-mobile con-66 | ASIA Miner | May/June 2012