Lifting ‘big iron’ takes big capacity and precise control
By Russell A. Carter, Contributing Editor
As a major buyer and user of equipment that includes shovels weighing millions of pounds, grinding mills that measure 40 ft or more in diameter and stacker reclaimers large enough to handle massive stockpiles, the mining industry has always been a steady customer for the specialized equipment and expertise needed to lift huge machines into position.
For mine project owners and managers currently contending with cost escalation from global inflationary pressures on everything from machinery to manpower, the prospect of having a project delayed because a major component can’t be lifted into place in a safe, timely fashion is increasingly unacceptable. In response, the major heavy-lift companies that regularly participate in large industrial projects such as mine construction have been busy adding new machines and capabilities to meet the changing nature of the businesses they serve, and lifting-equipment OEMs are expanding their product lines to provide machines tailored to meet specific needs as well as the industry’s wider focus on digital platforms and automation.
New Challenges, Novel Solutions
Cranes have always been the workhorses of heavy lifting and crane technology is steadily advancing. However, heavy-lift service providers and their customers are also being increasingly challenged to find solutions for accomplishing unconventional lifting jobs.
As an example, a common heavy-lift problem — moving a component that can’t be directly reached with a crane — is the focus of an innovative device highlighted by Barnhart Crane, a Tennessee, USA-based lifting and rigging company. The Movable Counterweight Cantilever System, which Barnhart calls MegaMOCCS, offers a solution that doesn’t require the site modifications often needed to move an item that may be unreachable from overhead or is located in close proximity to processes or machines that can’t be interrupted.
MegaMOCCS is an engineered cantilever system with beams and counterweights that can be adjusted to variable lengths and multiple rigging configurations. Once the beams are extended to the necessary length to reach and support the item, the counterweight adjusts remotely to balance the load as it is crane-lifted. The system’s maximum capacity is 200,000 lb at 11-ft extension, 55,000 lb at 45 ft and it can navigate ultra-low headroom situations.
Heavier Lifts, Higher Maneuverability
Heavy-lift service providers are adding higher-capacity and higher-tech units to their crane fleets, and mine/plant/terminal operators are employing a new generation of mobile and overhead crane models to meet current and anticipated future needs.
Liebherr updated its popular LRT 1100-2.1 rough terrain crane last year, giving it a heavier but more compact counterweight to increase lifting capacity while providing better operator visibility in all directions. One of the new cranes was used later that year to speed up the assembly of a Liebherr T264 mining truck at a site in Virginia, allowing the job to be completed four days ahead of schedule.
“It can be very hard to schedule cranes for builds like this,” said Thomas Coenen, Liebherr Mining Equipment product support representative. “Auxiliary cranes are often shared and used for maintenance of heavy mining equipment and other lifting needs around mining sites. In this instance, I was able to use the upgraded LRT from [a] crane rental. Using one crane that can lift the truck makes the project easier, and we can complete the build faster. This also meant no downtime or crane changes for different components to be lifted.”
An array of safety features come standard with the LRT, including the Variobase variable outrigger system that allows safe operation of the crane with asymmetric outrigger positions integrated into the LMI (load moment indicator). The crane also offers the LICCON controlled load moment limiter that Liebherr says minimizes accidents and human error, and a monitored two-hook operation that enables safe rotation of loads.
During the April 2022 introduction of its LR 12500-1.0 crawler crane, Liebherr noted that demand from the market for larger crawler cranes is growing because project lift weights are constantly increasing. Concurrently with the crane’s unveiling, Belgium-based heavy-lift specialist Sarens announced that it would be the first company to add the 2,500-mt-capacity LR 12500-1.0 to its fleet of more than 1,500 cranes. The LR 12500-1.0 fits between Liebherr’s 1,350-mt LR 11350 and the 3,000-mt LR 13000 – a model which Italian heavy-lift specialist Fagioli recently added to its fleet. Two Liebherr 6-cylinder in-line engines deliver a total of 800 kW (1,088 bhp) on the LR 12500-1.0. The maximum hook height of 200 m (656 ft) is achieved using a 100-m main boom and a 108-m luffing jib. The crane’s 110-m-maximum length ‘High-Performance Boom’ can be extended to 155 m (508 ft) using parts of the luffing jib.
US-based crane manufacturer Manitowoc expanded its line of rough-terrain cranes and highly maneuverable truck models last year, using bauma 2022 as an opportunity to launch the Grove GRT8100-1, which offers a list of improvements over the popular GRT8100 model. Many of the enhancements on the 100-ton-capacity GRT8100-1 stem from a new chassis that shares commonality with the chassis from the company’s 120-ton-capacity GRT8120. There’s also an updated engine and transmission package, and a new, wider cab with enhanced operating features.
The new crane, according to Manitowoc, features the same 360° load charts as its predecessor and has the same overall dimensions, counterweight and five-section 12- to 47-m (39- to 154-ft) boom. However, with the new chassis on the GRT8100-1 customers can choose to integrate the company’s MAXbase variable position outrigger system, which offers up to 15% capacity improvements in certain configurations. Also new to the outrigger design is an auto-level feature for easy jobsite set-up, as well as Manitowoc’s smart, length-sensing Outrigger Monitoring System (OMS). Powered by a 6-cylinder, turbocharged and water-cooled Cummins B6.7L Stage 5/Tier 4 Final compliant diesel, the GRT8100-1 offers approximately 10% more power, producing 224 kW (300 hp) at 2,500 rpm.
Manitowoc noted that Indonesian gold miner PT Arafura Surya Alam (ASA) recently purchased its first Grove crane: a GRT8100 which will be used to support a major construction program, as well as regular mine operations and plant maintenance duties. The company said ASA chose the GRT8100 to meet its need for a rough-terrain crane with the ability to work in tight spaces while being supported by an in-country dealer with parts, service, training and technical support. The crane supplied to ASA is the third GRT8100 to be delivered to Indonesia.
The GRT8100 has a capacity of 100 t and up to 73 m (240 ft) of reach when the 47-m (154-ft) main boom is fitted with its full complement of jib and intermediate lattice section. Power comes from a Cummins QSB6.7L diesel.
Manitowoc also expanded the range of solutions available to customers looking for a truck-mounted crane that can handle narrow, meandering roads and maneuver in confined spaces. The company’s new four-axle, 115-t-capacity TTS9000-2 truck crane features an automated steering system that helps operators navigate challenging driving conditions. On the TTS9000-2, each of the all-wheel steering modes can be activated by the operator at the click of a button. With crab steering selected, all tires point in the same direction when the steering wheel is turned, allowing the crane to travel diagonally. Another option is a coordinated mode where the driver turns the front wheels in the direction of travel and the rear wheels turn in the opposite direction. This reduces the truck crane’s turning radius and makes tight turns much easier, according to the company.
This article was excerpted from a much larger feature article that was published in the February 2023 edition of Engineering & Mining Journal (E&MJ).