Your complete guide to new and updated equipment and supplies in the aggregates industry.

By Kerry Clines, Senior Editor

Doosan’s large crawler excavator

Doosan says its new 72.1-metric-ton crawler excavator is the largest one the company manufactures. Designed for heavy-duty mining and quarrying applications, the DX700LC is powered by a 463-horsepower turbocharged Isuzu diesel engine and has an operating weight of 158,953 pounds with standard boom and arm, 35.4-inch double grouser shoes, and a 4.32-cubic-yard bucket. Bucket breakout force is 78,485 pounds with the standard bucket; arm breakout force is 64,595 pounds.

The machine’s long carriage design, combined with the 13-foot, 11-inch width of the fully expanded undercarriage, is said to offer stability and safety in all applications. The excavator works efficiently on slopes with a high swing torque of 48,369 pounds and a swing speed of 7.1 revolutions per minute.

Specifications

Engine 6-cyl., 463-hp turbocharged Isuzu diesel

Operating weight 158,953 pounds

Standard bucket size 4.32 cubic yards

Optional bucket sizes 3.27 to 5.89 cubic yards

Bucket breakout force 78,485 pounds

Arm breakout force 64,595 pounds

Swing torque 48,369 pounds

Swing speed 7.1 rpm

Drawbar pull 107,806 pounds

Max. digging reach 42 feet, 7 inches

Max. digging depth 27 feet, 7 inches

Dump height 27 feet, 4 inches

Max. travel speed 2.9 mph

A new control system includes four operating modes:

• Power mode for heavy-duty digging and loading;

• Standard mode for heavy-duty dumping, and for general and breaker operations;

• Economy mode for medium-duty digging, loading, and dumping; and

• Lifting mode for lifting pipes or beams.

The unit boasts a positive control piston pump and open center valve, which enable fine metering of hydraulic flow for smooth, precise control of machine functions. Flow regeneration conserves energy and enables increased boom and arm cycles. Boom and arm cylinders are cushioned to provide smooth end-of-stroke operation, while the holding system prevents attachments from falling when the controls are in neutral.

An automatic two-speed travel system controls travel speed and tractive force. In high range, maximum travel speed is 2.9 miles per hour.

The cab offers ergonomic controls and instrumentation. Joystick control stands raise and lower with the suspension seat while the seat itself slides forward and back to accommodate the operator. The unit is designed to keep machine noise levels as low as possible — noise level at the operator’s ear is 76 dBA, while noise level for bystanders is 108 dBA.

The machine features extended, 500-hour engine service intervals. Other maintenance features include:

• Wide side access doors;

• A large-capacity engine air pre-cleaner that removes airborne particles and extends filter cartridge service life;

• Dual fuel pre-cleaners, including a pre-filter that removes moisture from the fuel;

• A PC monitoring function that enables connection to the e-POS system.

The DX700LC is covered by a 48-hour parts guarantee — if a “machine-debilitating” part is needed, Doosan will deliver the part within two business days or pay for a replacement machine rental.

High-capacity screen

Smico Vibratory Screeners and Feeders says it designed and tested a new high-capacity screen. The standard large-capacity unit is 5 feet wide by 12 feet long with 360 square feet of screening area. The largest unit is 5 feet by 18 feet with 540 square feet of screening area. The screen imparts a vertical, bouncing motion and comes in a choice of three different brute force drive types — single-shaft elliptical drive, dual-shaft linear motion drive, and twin canned-motor style drive. These drives are said to be up to 30 percent more efficient than gyroscopic motion drive types.

Harp wire reduces downtime

Major Wire says its new LFM Harp Wire helps aggregate operations increase throughput over standard harp or piano wire while reducing downtime caused by worn wire cloth. The new wire is manufactured with straight wires firmly molded into polyurethane strips that hold the wires in place at the crown bar, eliminating steel-on-steel wear. The polyurethane strips are said to keep the wires equally tensioned, creating better wire vibration, reducing blinding, and increasing production of a cleaner aggregate. The company says its new wire handles high-impact loads better and lasts up to twice as long as conventional harp and piano wire.

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