North Star

(pics of the previous model 797B, the only difference is the new engine and drivetrain)


Cat® C175 Engine, Refined Drive Train and Efficient Body Designs
Assure Low Cost per Ton for 797F Mining Truck

First as the 797, then as the 797B, the design of the largest Cat mining truck has proven its productivity, durability and low cost of operation through more than 10 years of service in the world's most challenging mining operations. Now, the 797F, with 4,000-horsepower (2983 kW) and rated payload capacities to 400 tons (363 tonnes), combines the strengths of its predecessors with a new engine, redesigned operator station and custom body systems to deliver even lower costs per ton—with less environmental impact.

The 797F also offers easier maintenance and enhanced safety provisions. Ground level service points ease access, and 1,000-hour hydraulic filter service intervals reduce required maintenance. Safety enhancements include wider walkways, a rear access ladder and a bumper-mounted, three-way, lock-out tag-out box.

The 20-cylinder, 4,000-gross-horsepower Cat C175-20 ACERT engine has a single engine block and is the heart of the new truck. The engine has accumulated more than a quarter-million hours of field testing in mining trucks and power-generating systems. The C175 displaces 5.3 liters (323 in³) per cylinder—for a total displacement of 106 liters (6,458 in³). The 797F develops 450 horsepower more than its predecessor, the 797B, which used a 24-cylinder Cat 3524B engine displacing 117 liters (7,143 in³).

The cross-flow engine design uses four turbochargers, an air-to-air aftercooler and an electronically controlled common-rail fuel system, which precisely delivers multiple injections in a single combustion event. These electronically controlled systems account for much of the high power density and low emissions and contribute to the 797F fuel efficiency and responsive performance. The engine meets EPA Tier 2 emissions standards. The engine-cooling system, also electronically controlled, uses the engine cooling fan only as needed, which conserves power and fuel.

The engine control module, the Cat ADEM™ A4, has 50 times the computing power of its predecessor. The new module monitors more than 30 critical engine functions, drives the 20 fuel injectors and communicates more than 100 engine parameters that describe engine health and assist in diagnosing problems.

Controlling horsepower
A robust drive shaft transfers the immense torque of the C175-20 engine to the rear-axle-mounted, seven-speed planetary transmission, which delivers a smooth flow of power through the massive rear axle to double-reduction final drives. An integral lock-up torque converter enhances high speed performance and fuel efficiency.

The Cat Electronic Clutch Pressure Control system effectively manages transmission-clutch operation under varying speed and load conditions, assuring that gear changes occur with no power loss and that clutch engagement is modulated to promote smooth shifts and long clutch life. A separate fluid system assures a dedicated supply of clean, cool oil for clutch operation and transmission lubrication. Transmission features include engine over-speed protection, downshift inhibitor (at high speeds) and programmable top speeds.

The 797F integrated braking system combines three brake functions (primary, secondary and parking) with an automatic, hydraulically actuated retarder in a single assembly located at each wheel. These immense, oil-cooled, multiple-disc assemblies provide a total braking/retarding surface of 51,250 in² (330 645 cm²). An integral heat exchanger controls brake-oil temperature to maintain no-fade performance and to extend brake life.

Frame and body systems
A robotically welded and ultrasonically checked frame incorporates nine mild-steel castings. The large radii castings are resilient to absorb frame flexing and ensure long life. The mild steel castings and fabrications provide flexibility, durability and resistance to impact loads, even in cold climates.

Available for the 797F is a choice of four Mine Specific Design (MSD II) body options that can be used in conjunction with a configurable liner system to provide an optimal blend of payload capacity and durability in a given application. Customers can tailor body systems to production demands and operating constraints, and payload capacity can be as much as 20 tons (18 tonnes) greater in some instance than was available with the 797B.

Operator station, machine management and safety
An angled, center-mounted instrument panel and a center console are the dominant features in the 797F new operator station. Analog-type gauges are quickly checked without losing sight of the haul road, and the integral Vital Information Management System (a powerful third-generation configuration) provides machine health and payload data, plus easy access to diagnostic and machine management information. The optional Road Analysis Control system monitors frame rack, bias and pitch—facts that can be used to make haul road improvements that promote quicker cycles, increased fuel efficiency and longer frame and tire life.

Levers and switches in the console are comfortably positioned just forward of the right armrest to allow easy control with minimum effort. Two fully adjustable, air-suspension seats assure comfort throughout the work shift for both the operator and trainer, and newly designed front and side windows give a commanding view of the haul road and work areas. A wide stairway and walkway, plus guard rails, help to provide safe entry and exit, and wide-angle mirrors, body-raised indicator, body-retaining cables and reverse-neutralizer further promote safe operation.

JonBoy

I've been next to the current generation 797 trucks, including sitting in the cab with an operator in a Bucyrus 495 shovel and watching him fill them up (takes less than four scoops!). They're huge! 11,500 lbs for a single wheel/tire assembly. At 60 mph, you can still see the individual treads of the tires (watching from behind) because they're rotating so slowly due to their height. Another interesting tidbit is that the drivers for these things in northern Canada are starting to be mostly women due to their higher TOT (Time on Task).

Here are a few pictures next to normal vehicles and people, just for size reference. You have no idea how big these are until you park next to one!







I can fit my rental house in the bucket of one of these trucks (it's a relatively narrow, two-storey house)...

North Star

Damn JonBoy, that must have been a site to see!! Lucky man!

I'd love to own one just for the sheer awesomeness of it. They go for about $5mil, so I'd have to win the mega millions lottery or something. I wonder how much it would be to fill up one of these behemoths?

Not Sure

Too big for my driveway.

North Star

This thing is literally as big as a house! Would be sweet to have in a zombie apocalypse, fully gassed and ready to roll!

North Star

Look at this motor!

JonBoy

I was at Shell's Jackpine mine last week and had two of them dumping (above my head!) into the primary feeder for the crusher. You can't imagine how much those dump beds hold until you see them dumping right in front of you. Absolutely phenomenal. There were chunks of sand roughly the size of a Smart Car (but weighing about 2 tons) tumbling out the back end and straight down into the crusher. I could've watched all day. It just completely redefines "BIG" in your mind!

North Star

That is so cool man! What do you do to be able to see these things in action?

JonBoy

I'm the Product Development Manager for a mining and oil sands consumables manufacturer. They do everything from buckets/GET (teeth, lips, shrouds) to crawler shoes/systems and undercarriages for the big shovels as well as wear block and plate, crusher tips, dragline equipment (rigging, buckets, teeth) and also mining parts like bullnoses, mill liners, etc, etc. So, I get to go into pretty much every part of the ore extraction, prep and processing sites.

North Star

Sounds like a pretty fun job!

What kind of training would one need to drive one of the 797's?