Wk 1.2 Theory of constraints applied to mining

Question 1

What is TOC

Answer 1

Theory of Constraints

Question 2

Where did TOC originate from

Answer 2

From the manufacturing sector and is now applied to mining

Question 3

What are process maps

Answer 3

a way of documenting the sequence of tasks and when it occurs

Question 4

What do the following shape symboles correspond with on the map:
Circle -
Square/rectangle -
arrow -
diamond -
semi circle -
torn page -

Answer 4

Circle - beginning or end
Square/rectangle - activities
arrow - process flow direction
diamond - decision
semi circle - delay
torn page - document

Question 5

What does takt mean in german

Answer 5

a baton that an orchestra conductor uses to regulate the tempo of the music

Question 6

What is takt time

Answer 6

it is though of as a measurable “beat time”, “rate time” or “heartbeat”.

Question 7

In manufacturing what is takt time

Answer 7

it is the rate at which a finished product needs to be completed in order to meet customer demands

Question 8

What does lean manufacturing come from

Answer 8

toyota production system in the 1980s and is now used in mining

Question 9

What is the equation for takt time

Answer 9

takt time = working time available/customer demand

Question 10

what changes in the takt time equations for mining

Answer 10

the customer demand can be completed in tonnes or loads

Question 11

How can a bottle neck be determined

Answer 11

when the cycle time exceeds the takt time and is a larger quantity than other process it is seen to be a bottle neck as it takes a longer period of time

Question 12

When implementing continous improvent processes where should the money be allocated

Answer 12

it should go towards the bottlennecks of the operation

Question 13

What is rate in terms of takt time

Answer 13

rate is the inverse of takt time

Question 14

what is the equation for volume produced

Answer 14

mean rate X production time

Question 15

what is used instead of takt time in mining

Answer 15

production time

Question 16

what is the equation for production time

Answer 16

available time X utilisation X calander hour availability

Question 17

what is mean rate

Answer 17

the average rate that is able to be produced

Question 18

how can the volume produced by a mine be increased

Answer 18

increasing the productioin time
this can be done through increaseing availability and/or utilisation

Question 19

What is MDR

Answer 19

Maximum Demonstrated rate

Question 20

what does the variance in production rate show

Answer 20

The difference between the top point of the MDR and the mean rate.

Question 21

Where does inherent variability in production come from

Answer 21

the variance

Question 22

What is the goal rate to sustain

Answer 22

the aim is to maintain the highest demonstrated rate

Question 23

Where are challenges in increasing the production rate come from.

Answer 23

Challenges come from the variance in rate aims to understand where it comes from and how it can be stabilised.
Other challenges are how to push the whole rate towards MDR

Question 24

What is a current initiative to increase a production rate (increase truck rate)

Answer 24

increase in truck payload where the main variable when keeping the same truck but increasing the load is the tire type.

Question 25

What is a risk with the increase in production time

Answer 25

the bottleneck could move further down the production line and be capped at the mill or trains

Question 26

What is the combined effect and its aims

Answer 26

The improvement of both rate and production time

Question 27

What process is a metal output per unit time contrainsed by

Answer 27

a limiting process

Question 28

What are examples of limiting processes

Answer 28

*development limited
*mining limited
*processing (mill) limitied
*rail or port limited

Question 29

What are examples of contraints or bottlenecks

Answer 29

*rate restrictions
*production time restrictions
*rehandle

Question 30

What do you need to develop constraints

Answer 30

you need to understand the rate restricted or time restricted

Question 31

Examine the examples in the lecture on identifying the contraint (investigate app pro options)

Answer 31

pending

Question 32

What is availability

Answer 32

the ratio of available hours had to produce divided by the total calendar hours

Question 33

What is system availability

Answer 33

This occurs when they are mutually exclusive the product of available of the individual component avaialble

The system is based off the individual component

Question 34

How should the unit availability and reliability be for complex systmes

Answer 34

very high

Question 35

What happens to relability as a system gets more complex

Answer 35

the more complex the system the higher reliability that is demanded

Question 36

What do parallel systems come with

Answer 36

redundancy

Question 37

What is the system availability of a parallel system

Answer 37

it is 1 - probability that all of those systems fail

Question 38

What do N out of n systems represent

Answer 38

they are like a mine where a required amount must function for the whole system to function

Question 39

what is the system availability of a n out of N system

Answer 39

1 - probability that none are available

Question 40

What is an issue with shovel and truck matching equation

Answer 40

it assumes 100% availability of trucks and loaders

Question 41

Why must trucks and shovels be matched

Answer 41

matching avoids excessive over or under trucking of the loader or shovel

Question 42

What does a match factor of >1 and <1

Answer 42

> 1 is equivalent to an overtrucked operation
<1 is equivalent to an undertrucked operation