Recommend

Recommend guide
guide for
for
PC2000-8
PC2000-8 BackBack Hoe’s
Hoe’s
larger
larger bucket
bucket

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For salesman
■The purpose of this guide
The standard bucket for PC2000 is 12.0m3 (with Hensley teeth). In addition to 12.0m3
bucket for PC2000-8 , the larger 13.7m3 bucket is prepared for improving its productivity
by reducing the loading cycles per truck.

■Remarks
1. Originally, the 13.7m3 bucket are supposed to be used at the site with the material of
less than 1.5 t/m3 loose material density. Depending on conditions, the bucket can be
used up to 1.8 t/m3 loose material density. Site conditions (work conditions and soil
conditions) which the larger bucket can be used are described in this guide.
Please read through this guide and get customers' understanding by providing them
with sufficient information.
2. PC2000 with 13.7m3 bucket can fill up HD785 by four cycles. As long as the loading
cycles per truck is concerned, PC2000 with 13.7m3 bucket and PC3000 with
standard 15.0m3 bucket is the same. But PC3000 is superior to PC2000 on the
standpoint of engine horsepower and digging power. If material of the site is hard,
performance of digging clearly differs between PC2000 and PC3000, therefore, as a
result, productivity will be way different.
Depending on the site conditions, PC2000 cannot achieve customers' production
target but PC3000 can. PC2000 should be recommended to customers based on the
understanding that the following points are advantages of PC2000.
① less expensive of price than PC3000
② fuel consumption is lower
③ cost per production is less

Contents
1. Proper use of standard bucket(12.0m3)and larger bucket (13.7m3)
① Features
② The condition which larger buckets can be recommended
③ The effect of larger bucket
④ Things to be considered when recommending larger bucket
2. Example of actual usage
3. Reference
① Types of bucket
② Method for selecting bucket

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1.Proper use of standard bucket (12.0m3) and larger
bucket (13.7m3)

① Features
12.0m3 13.7m3
(Standard bucket) (larger bucket)
Features ・Applied to ・larger capacity (+14%) and applied to loading and easy
loading and excavation.
excavation. ・Reduction of loading cycles per truck.→see③
･General purpose ・Increase of production volume
・Material density ・Material density (loose) ≦1.5 t/m3
Notice (loose) ≦1.8 t/m3 ・Material density (loose) ≦1.8 t/m3 ---in case of easy
digging such as well blasted material or loose soils.
・Not suitable for hard digging due to increased width.
・Digging time and swing + hoist time are longer, and a cycle
time per bucket becomes longer.
・Bank to be stable for bearing heavy load.

② The condition which larger bucket can be recommended

・The material density (loose) to be less than 1.8 t/m3
・Light jobs and easy excavation of well blasted rocks or loose soils.
（It doesn't get good effect at an clay stone .）
・Bench height should be 3.0 to 4.0m and be stable for bearing machine
weight.

Working range and machine setting

Condition
･Lower level loading to HD785-7
･Bench height =3.5m
･Distance to edge of bench=0.5m
･Distance from tire to slope of bench=0.5m
･Angle of repose=45°

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③ The effect of larger bucket
(1) Reduction of loading time

Increase of bucket payload

Decrease of bucket passes

Reduction of loading time & Increase of production

Image : Loading time reduction（Loading to HD785）

Truck
1 bu c ke t 2 bu c ke ts 3 bu c ke ts 4 bu c ke ts Setting
13.7m3 time

Truck
12.0m3 1 bu c ke t 2 bu c ke ts 3 bu c ke ts 4 bu c ke ts 5 bu c ke ts Setting
time

Time
Note : As the time of each pass becomes longer , total loading time may not be 4/5 per 1 dump truck.

(2) Increase of production

(1,000Ton/y) (Ton/h)
10,800 3,000
Calculation Condition:
Job efficiency 13.7m3
13.7m3 Bucket 70% 12m3 Loading material : Blasted rock
9,000 2,500 Cycle time:30sec Material density (loose) : 1.8 t/m3
Approx.1,860 ton/h Bucket fill factor : 0.9
7,200 2,000
● Operation hours : 12h/Day
Production

● 25days/Month
3600h/year
5,400 1,500
Types of loading : Lower level loading

3,600 1,000
12.0m3 Bucket
1,800 500 Cycle time :28sec
Range of actual using
Approx. 1,750 ton/h
0 0
20% 30% 40% 50% 60% 70% 80% 90%
Job efficiency (%)

Range of actual job efficiency is approximately 30%-70%

The production difference between 12.0m3 bucket and 13.7m3 bucket is 110ton/h in case of
70% job efficiency , and 396,000 ton/year.
Job efficiency: Index which indicates how much various elements have adverse effect
on production volume. Elements such as operators’ skills, difficulty of operation, daily maintenance time, etc.

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(3) Comparison example

As the chart below shows, cycle time and production volume differs greatly depending on operators’ skills.
High operators’ skill is imperative to use the 13.7m3 bucket effectively and improve customers’ productivity.

＊This chart was made based on our example. The numerical value isn't guaranteed.

Operator skill Low (less experienced) High (experienced)

Dump truck HD785-7

Material density [loose](t/m3) 1.8
Swing angle (degree) 45-90
Bucket capacity (m3) 12.0 13.7 12.0 13.7
Loading cycles / truck 5 4 5 4
Cycle time / bucket (sec) 30~33 32~35 26~28 28~30
loading time / truck (sec)※1 165~180 143~155 145~155 127~135
Production volume ratio 1.0 1.07 1.15 1.23
※1.Truck setting time was calculated 15 sec.

④Things to be considered when recommending larger bucket.

Before recommending larger bucket, you have to understand and give proper explanation
about the following points to the customer.

1. As the burden of larger bucket is heavy, time required for digging, and
swing becomes longer and cycle time per bucket becomes longer.
2. At the site of hard material (Blasting was not well or not adequate.) or clay site,
digging power and the full capacity per bucket is not very good.
It means loading cycles per truck will not be reduced.
3. With increased front weight (bucket & load) , the machine stability becomes less.
Therefore , the bank of bench should be stable for bearing the machine weight.

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2. Example of actual usage

① Effective case・・・Excavating coal overburden

･Excavation efficiency is high
because the bench height is
most suitable and blasting is
well.
･Cycle time is about 28sec at
45-90 degree swing angle.
･13% increase of production
comparing with 12.0m3 bucket.

3.0m

② Ineffective case ・・・Excavating clay stone

･Digging Hard due to hard and
tight clay stone at this site
where blasting doesn’t work.
･Cycle time was about 35sec
at 45-90 degree swing angle.
･Production was not enough.

Clay stone of blasting doesn’t work

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3. Reference
① Types of bucket

*1 Of larger bucket, straight edge and spade nose are chiefly the same but their bucket capacity are slightly different. This
results from a difference in rip shape. Therefore, when selecting between straight edge and spade nose of larger bucket,
please do not make selections just by the bucket size. You need to select rip shape to meet requirements of customer
considering how the excavator will be used.
Komatsu recommends straight edge of larger bucket but depending on the usage, some customer might wish to have
spade nose. You need to consider this point.

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② Method for selecting buckets
（○：Suitability ×：Unsuitability ）
Material density (loose) ≦1.8 t/m3
（ex.：Coal mine ,Limestone mine ）
Sand Rocks
& soil

well blasted badly blasted Not

Host rock doesn't remain after the Host rock remain after the blasting
blasting. blasting.
Most rocks are Most rocks are (ex. Clay
less than 30cm. over 30cm.
stone)

Host
rock

1m
1m

12.0m3 ○ ○ ○ ○ ○
selection
Bucket

13.7m3
14.0m3
○ ○ × × ×
＊Please consult mining person in charge of your local subsidiary or distributor when material density (loose)
is larger than 1.8 t/m3 like iron ore mine.