With correct crusher selection, installation and maintenance in place, material generally flows from the mine through the plant efficiently and without excessive trouble. Get any of those factors wrong— or err in specifying maximum feed size, secondary circuit feed size, necessary tons per hour, material characteristics or maintenance/ operating costs—and a number of unpleasant consequences can result.

Conversely, changes in upstream conditions, such as modifications to existing blasting practices or changes in ore characteristics, can result in problems that even the most carefully engineered crushing setup may find hard to handle.

In just about every instance of crusher problems, the stakes are big—because “big iron” is involved, purchase, repair and operating costs are significant; and constant, acceptable throughput rates are crucial for continuous production. Crusher manufacturers address these potential problems in a number of ways that include steady expansion and upgrading of their product lines with increasing emphasis on wear-parts improvement, crusher chamber design, and crusher protection systems; consultation and analysis services for crusher optimization; and proactive improvements to field service capabilities, parts delivery and training.

Crusher issues can sometimes be traced to economic pressures. In boom times, equipment is generally run at peak utilization rates and management may be hesitant to interrupt production for lessthan- major inspection or maintenance. In lean times, maintenance and pre-emptive parts replacement might be extended beyond recommended intervals. And in some cases, the simple desire to save money can actually result in higher costs.

Sandvik, for example, argues that productivity is the pivotal factor in any decision regarding the purchase of a crusher. However, users may sometimes get sidetracked by secondary issues, such as hours worked, manganese content or tons through the crusher. While there is no denying that these aspects are important, they only play a part in a bigger process: it is productivity—tons of end-product produced— that defines the actual return on investment for capital employed in the purchase of equipment, parts and service.

The Swedish manufacturer goes on to pose the question: Why is the highest crusher manganese quality paramount for productivity? The company, whose corporate expertise in crushing chamber design and wear part casting dates back to 1916, provides this answer: Experience has shown that substandard wear parts are often associated with inadequacies such as incorrect profile shapes, dimensions and ovality. All of these potentially have expensive consequences including reduced capacity and diminished reduction ratios, incorrect product gradation, increased circulating load and damage to bearings, bushings and other components.

The company says product development stems from a close working relationship with customers established through the services Sandvik provides, including training, and by continuous dialog.

The most recent product of the continuous development process is the patented Sandvik Flexifeed cone crusher mantle, which Sandvik claims will extend liner life and increase the reduction ratio through maximal utilization of the crushing chamber. This mantle features an extension at the intake that allows more crushing to take place in the upper section of the chamber, while large rocks can still be crushed where there is no extension. This translates into extended liner life and a higher reduction ratio through maximal utilization of the crushing chamber, the company says.

If You Build It, Will Orders Come?
In mid-September, Sandvik inaugurated its largest production facility to date, in the Shanghai Jiading Industrial Zone, China. The new plant is able to produce most of the products in the company’s range, from crushers to drill rigs and loaders. The new facility is larger in scope than the company’s also-new manufacturing operation at Vespasiano, near Belo Horizonte in Brazil. This 17,000-m2 facility—somewhat smaller than the 24,000-m2 Chinese plant— manufactures components for conveyor systems and will also be used to assemble cone and jaw crushers.

Metso recently announced an expansion of its crusher factory in Tianjin, China. The expansion will double production capacity at the plant and increase the factory’s total floor space to more than 7,500 m2. The manufacturing portfolio will be extended to include several new small crusher models and the factory will also start producing screens and feeders, allowing Metso’s other manufacturing units to focus on larger and tailor-made crusher models.

Metso Minerals completed an expansion at its Tampere, Finland, crusher plant and also established a research and
testing center at Tampere that allows full scale testing of commercially sized crusher models before they are shipped.

All of these expansions took place during the recent mining-industry boom years—and the companies remain optimistic that their upgraded and higher capacity manufacturing capabilities will pay off in the long run—but the global economic slump has taken its toll on this sector. With customers financially stressed, holding onto their available cash, using up existing parts inventories and canceling or delaying projects, mining equipment orders dropped by 40% to more than 60% in some cases, compared with the same period a year earlier. The major suppliers had to take survival steps.

In October, for example, Metso announced that it would lay off 76 hourly-wage and salaried employees at Tampere. This follows upon an earlier layoff of 112 workers at its Tampere and Helsinki operations as well as temporary layoffs for another 1,000.

Since late 2008, Sandvik has laid off 6,000 of its global workforce and imposed work-time reductions and salary cuts on another 12,000 to 14,000 of its workers.

These financial problems weren’t uniformly dismal, however, most of the larger manufacturers noted that business was expected to improve slightly throughout 2009 and 2010, and their customer-service/ aftermarket parts businesses generally performed better than their equipment sales during the worst months of the recession. This can probably be attributed, in part, to the continued efforts the majors have devoted to working closely with customers in maintaining and optimizing their crusher setups.

Metso, for example, recently pointed out that it has been involved with Kalgoorlie Consolidated Gold Mines since 2001 as the preferred contractor for servicing and maintenance of KCGM’s crushing and materials handling facility at the Fimiston plant in Kalgoorlie, Western Australia. Over time KCGM has seen the material produced from the open-pit—the largest in Australia—vary in both hardness and abrasiveness, but the technology available from Metso has been able to keep up with these challenges.

A key achievement during this time, said Metso, was to optimize the wear packages and profiles used in the primary crusher. According to the company, this has increased concave life by as much as 300% between changes, with the useful life of mantles increasing in a similar range.

It is also important to KCGM to have the guaranteed availability of the primary crusher at high levels. Metso upgraded the primary crusher from a Superior Mk1 gyratory to a Mk2 model. Following the upgrade KCGM has consistently seen a +95% availability on the crusher and conveyor system with very little unplanned maintenance.

Metso also recently signed a multi-year service agreement worth about €5 million with AngloGold Ashanti’s Iduapriem mine in Tarkwa in Ghana. The contract includes the supply of maintenance management services and spare and wear parts for the mine’s new 4.3-million-mt/y crushing and screening plant delivered by Metso. In addition to maintenance management and technical support, Metso will supply hands-on training for staff at the mine. Metso said it also is committed to converting the agreement into a cost per ton-based service over time.

Vendors, Customers Collaborate
The mining industry’s less-than-robust economic health hasn’t helped with new product introductions in the crusher sector. Nevertheless, there are some recently introduced crusher models on the market, and they are being bought—in some cases, by the dozen.

Sandvik’s CG series of gyratory crushers is a result of a
collaberation between it and Kawasaki EarthTechnica.
Shown here is a cutaway of the model CG850.

However, earlier this year Sandvik happily announced it had sold 12 of its CH880 cone crushers to the Sino Iron project in the Pilbara region of Western Australia. This greenfield project includes an open-pit magnetite mine and processing facilities, and will export about 27 million mt/y of concentrate and pellets. Crusher delivery is expected to be completed in 2009 and first production will start during 2010.

Sandvik said the end customer, CITIC Pacific Mining and its lead contractor China Metallurgical Group Corp. (MCC) worked closely with Sandvik representatives across Sweden, China and Australia to arrange the order. The 12 CH880s will function as pebble crushers and will be installed in six mill circuits with two crushers in each station and with a capacity of 1,300 mt/h per crushing station.

Prior to the Sino Iron contract, Sandvik reported the first orders for its CG series gyratory cushers—from three mining companies situated on three different continents. Cumulatively, the orders were valued at approximately €10 million.

The first of the three primary gyratory crushers, a CG820, was delivered to a unidentified mining company in Europe in August 2009. Another CG820 has been ordered by Tata Steel Ltd., based in Jamshedpur, India. The machine will replace the existing primary crusher which feeds ore to a steel plant with throughput of 6.8 million mt/y. The other gyratory ordered is a CG850. M3 Engineering & Technology Corp., together with Augusta Resource Corp., selected it for Augusta’s Rosemont Copper project near Tucson, Arizona.

Both the CG and CH lines emerged from Sandvik’s collaboration with Earth- Technica, a subsidiary of Kawasaki Heavy Industries.

More recently, a Kawasaki Earth- Technica primary gyratory crusher was installed as part of a plant expansion project at the Tati nickel mine in Botswana. IMS Engineering worked in partnership with project house DRA Mineral Projects. What makes this a notable event is that the KG15026EHD-S crusher, which features a 105-mt, 6-m-diameter spider, was commissioned in about 10 days, according to an IMS spokesperson, apparently a record for this type of installation.

Norsk Stein, considered the largest quarry in Scandinavia, ordered a complete fine crushing and screening system from Metso. The order comprises four gyratory cone crushers, eight inclined screens, a stacker conveyor, and other conveyor equipment. The order is part of Norsk Stein’s program to double annual output from just over 5 million mt/y to more than 10 million mt/y. The equipment and services order, according to Metso, is worth €27 million and the new plant will add an additional 850 mt/h of crushing capacity to an existing plant’s 650 mt/h.

Bigger and Better
FLSmidth’s Excel crusher division introduced the Raptor XL900 cone crusher, and bills it as the first high-performance cone crusher built with a rigid four-arm frame and integral countershaft mounted inside one of the four arms. This, said Excel, provides a stronger frame design and avoids pitfalls associated with an external countershaft box. The 900-hp XL900 cone has a maximum throughput capacity of almost 1,400 t/h (1,270 mt/h) and handles feed size up to 14.57 in. (313 mm) with a reduction ratio of up to 6:4.

Excel’s line of Raptor cone crushers also includes the XL1100, one of the largest cone crushers available on the market, along with the XL300, XL400 and XL600 models. The 1,000-hp XL1100 can deliver throughout of up to 2,240 t/h (2,000 mt/h) at a 1-1/3-in. (35-mm) closed-side setting. The unit handles feed size up to 24 in. (620 mm) and allows a reduction ratio of up to 6:4. Available with shorthead or standard bowls, the XL1100 cone is suited for secondary, tertiary and quaternary applications.

FLSmidth Excel’s Raptor XL900 cone crusher.

Wisconsin, USA-based Lippmann-Milwaukee’s latest large jaw model is the 5062. Displayed last year at MINExpo, the company emphasized at that time the economy of its design; for the price of one gyratory installation, it claimed, an operations could install two 5062 jaw crushers.

Telsmith’s top-of-the-line Iron Giant jaw crushers are offered in two sizes: 4448 and 5060. The 5060 and two smaller units in its standard line—the 3258 and 3042— have been designed with two-piece frames and low-clearance profiles that ease transport and installation problems underground.

Metso’s Nordberg C-series large jaw crushers such as its C160 and C200 also offer a design amenable to underground mines: nonwelded frames that can be disassembled on the surface and reassembled underground.

At the other end of the spectrum, Sandvik’s CJ200 series offers a combination of lightweight machinery suited for heavyduty crushing applications. The optimized crushing chamber of the newest member of the family, the CJ208, provides high reduction ratio and capacity. The CJ200 series’ wide range of applications also includes the possibility of producing a 0 to 1.5 in. (0 to 4 cm) final product in one crushing stage. The CJ200 series frames are welded, which Sandvik says makes them equally strong in all directions and ensures durability against shock loads. In turn, this minimizes the risk of mainframe failure.

The energy-conscious CJ208 requires only 74 hp to crush the hardest ore at the smallest feed settings, according to the company.