Loading and Hauling

Cycle Time = Fixed Time + Variable Time Fixed Time = spot time, load time, maneuver time, Dump time Variable Time = travel time Resistance Total Resistance = Rolling Resistance + Grade Resistance Rolling Resistance due to tire flexure and surface penetration Grade Resistance due to grade of incline

Rolling Resistance 40#/ton on hard surface rubber tired 30#/ton if radials T4-1 Rolling Resistance increases 30#/ton/1” penetration Rolling Resistance Factor = 40# + (30# * inches penetration) Rolling Resistance = Rolling Resistance Factor * tons

Grade Resistance % of vehicle weight acting parallel to incline surface Negative going downhill Positive going uphill 20#/ton Grade Resistance Factor = (20# * % grade) Grade Resistance = Grade Resistance Factor * tons Effective Grade (%) = % Grade + Rolling Resistance/20

Altitude 3% power loss per 1000 ft Using turbocharger allows power to stay constant up to 10,000 ft

Traction Power available to move vehicle Rimpull – used for wheeled vehicles Pull available at rim of driving wheel Drawbar pull – used for tracked vehicles Power available at hitch Maximum usable pull = coefficient of traction * wt on driven wheels (for tracked vehicles and all wheel drive vehicles this is total wt) T 4-2

Performance Curve Retarder curves Maximum speed for a given load F 4-1, 4-2 Retarder curves Maximum speed going downhill in gear

Travel Time Cannot use max speed Need to account for start up and stop Average speed factors T 4-3 Max spd * Ave spd factor = speed for haul

Dozers Tractor w/ front mounted earthmoving blade Crawler Rubber tired Low ground pressure (6 – 9psi) Excellent traction Rubber tired Hi spd Can compact soils Can operate on paved surfaces

Dozers Attachments Rakes, scarifiers, rippers tow compactors, scrapers, wagons Blades F4-7, F4-8 Performance based on power vs blade size Hp/ ft of cutting edge -> blades ability to penetrate hard soils Hp/loose cy -> blades ability to push soil

Production 5 bullets pg 96 show how to determine blade volume Blade load (LCY) = 0.0139HWL Fixed cycle time – maneuver, change gears, start loading, dump Variable time – time to doze and return Can decrease by using reverse to return T4-4, 4-5

Job Management Downhill dozing Slot Dozing Blade to Blade Increases blade load Cycle time reduction Slot Dozing Increases blade capacity up to 50% Blade to Blade 2 dozers together Combined capacity > 2x 1 dozer

Care for tracks and undercarriage Must keep tracks clean Must keep undercarriage clean and in good repair Don’t run at hi spd over rough terrain Minimize turns Try to balance left and right turns and up & down slope operation

Loaders Tractor with a front end bucket Wheeled or tracked Excavate soft – medium hard material Load hoppers and haul units Stockpile material, backfill ditches Moving material

Loaders Wheel Loaders Tracked Loaders Backhoe loader F 4-11 High mobility Not all terrain but low ground pressure Modern are articulated F 4-9 Tracked Loaders Can operate in most soils and on steeper slopes Slower over longer haul distances=> less productivity F 4-10 Backhoe loader F 4-11 Attachments – augers, snow blades, forklifts, dozer blade, crane booms

Skid Steers Small wheeled loader w/ rigid axles Steers by braking wheels on one side <10,000# weight Lift capacities of 600 – 6300 # Can also be tracked List of attachments pg 100 Also mini excavators

Material Handlers Rough terrain forklifts Common Lull Max lift 9000# Max height > 60 ft Move materials around site Eliminates hand carrying or use of other equipment for carrying

Loader Production Average Bucket load x cycles per hour Cycle time = loading, dumping, making 4 reversals in direction, traveling minimum distance T 4-6, F 4-14 Bucket Capacity is heaped T3-1 and use fill factor T3-2 Ex 4-7

Job Management Cutting tires major problem L-5 tires – rock extra deep tread should be used when dealing with shot rock Keep water out – lubricates rock /rubber cutting Need to know tipping load – may limit amount of material in bucket Loader size & productivity based on site limitations