Cable costs

Question 1

What is standard unit cost?

Answer 1

($ x hours) divided by production per day

Question 2

What are the elements of a cable Yarding cycle?

Answer 2

Outhaul time: time for grapple or chokers to make it from roadside to log (function of distance and line speed)

Hookup time: time taken for the grapple to open, drop onto the log and close (or chokermen to wrap logs (40-50% of cycle ).

Inhaul: time taken for a grapple (or chokers) to travel from the woods to the roadside and log is dropped on a log deck (function of distance, line speed, turn size, slope)

Decking: time taken for the yarder to straighten up already decked logs

Question 3

What’s the main dif between grapple and tower Yarding?

Answer 3

Tower needs Chokerman. Adds hookup time

Question 4

What does change roads refer to?

Answer 4

time taken for the hooktender to reposition the tailholds

Question 5

What does spot refer to?

Answer 5

time taken for the hooktender to check a yarded row for merchantable stems

Question 6

Delay

Answer 6

when the yarder is not actively yarding logs (mechanical or operational, upend chokers, hang-ups…)

Question 7

Abort

Answer 7

time taken to drop an non- merchantable log and return to get another

(in choker systems this won’t happen) chokers would have inspected it.

Question 8

What variables effect cable productivity?

Answer 8

1. Size of setting - fixed elements like equipment moves are written off against a higher volume so they will drop.
2. Volume per ha. - high yield/ha results in proportionally less delay and less time changing roads.
3. Volume per log
4. Slope - inhaul time
5. Yarding distance - out and Inhaul
6. Landing size
7. Deflection

Question 9

WHats a typical highlead time breakdown?

Answer 9

1. Outhaul – 8%
2. Hookup – 41%
3. Inhaul - 19%
4. Unhook – 22%
5. Delay – 10%

Question 10

How is the proportional time of each part of a cycle quantified?

Answer 10

Work Sampling: take spot observations of the elements at predetermined times. Also make note of operating variables and production.

Question 11

What are some aspects of grapple yarders in comparison to tower and swing yarder with chokers.

Answer 11

• GY spends proportionally more time moving rigging
• GY spends proportionally more time on repairs
• GY spends less time on non- mechanical delays
• less stems per turn, but faster cycle time

Question 12

Why does GY spend more time on road change?

Answer 12

Moving two machines at once

Question 13

Why is loading and bucking higher in tower systems?

Answer 13

Has to buck and load at landing to keep yarder going.

Question 14

What does unit cost refer to?

Answer 14

$ per m3