វទិ្យាស្ថា នបច្ចេកវទិ្យាកម្ពជុាInstitute of Technology of Cambodia

Group Presentation

Course Title: Surface Mining & Underground Mining

Lecturer: Dr. Bun Kim Ngun

20151

Department of Geo-resources and Geotechnical

Engineering

Group Members and Responsibilities

Phon Somony In Sopheak Hun Lihour

Content

I. Introduction

Exploration methods

1. Excavation, logging, and Analysis

2. Metallurgical/ Process testing

II. Reserve estimation and Evaluation

Classical Methods

Weighting Methods

Feasibility study( economical interest)

III. Shovel selection

IV. Belt Conveyor

• Surface Mining

• Underground Mining

V. Truck Haulage

VI. Reference

Objective

Clearly identify the terminology of Resource and Ore reserve

The audiences be able to understand the basic of Estimation methods

and Evaluation

Get more idea about production rate and economic interest

The utilization of material or Truck

Risk and Challenges determination

Analytical and Critical Feasibility study

The process of production and production rate

I. Introduction

Traditional geometric and geostatistic methods for reserve estimation in a single

deposit are difficult to use with skewed distribution mineralization variables including

grade, orebody thickness and grade–thickness, common characteristic of most deposits.

In this topic, it related to the two types of terminology

1. The Resources: is a concentration of naturally occurring solid, liquid or gaseous

material. Resources can be divided in to 3 parts.

1. Measure mineral resources:

2. Indicate mineral resources

3. Inferred mineral reserve

I. Introduction (Con)

2. Mineral Reserves: is the portion of a measured or indicated mineral

resources that is economically minable. In this part, there are two sub-

categories.

Prove mineral reserve

Probable mineral reserve

Exploration methods

1. Excavation, logging, and Analysis

2. Metallurgical/ Process testing

II. Reserve estimation and Evaluation

The reserve estimation is the main part of mining methods. Ore reserve estimation has

crucial importance for the evaluation and exploitation of mineral deposits.

The Reserve estimation is divided in to two main methods

Classical methods

Weighting methods

Classical Methods

The geometric methods has many sub-methods and options:

1. Triangle

2. Regular

3. Square

4. Rectangular

5. Polygonal

6. Other geometric blocks

The Geometric block method is one of the most popular method

for reserve estimation. Orebody area can then be manually

separated into numerous blocks with exploration, orebody

horizontal or vertical thickness and the local reserve in each

block are calculated according to the exploration works.

Grade and Tonnage Calculation

Classical Methods

Polygon Method

Triangle Method

Section Method

Classical Methods

1. Drill hole plan

2. Connecting line

between drill holes

3. Connecting lines

4. Final polygon

Polygon Method

Reserve estimation

Weighting Methods

Weighting method or Geo-statistical method provide a logical procedure for determination of a

block of material base on sample gathered within a given region of the block.

The geostatistical method is used

primality after a large mass of data

has been collected on the deposit

and the characteristics of the ore

grade distribution are well known.

Weighting Methods

A geostatistical reserve estimate generally entails these following steps:

1. Study of geologic control on mineralization and identification of any

zoning within the deposit.

2. Computation of semivariogram of each zone within the deposit.

3. Division of this ore body in to geometry block

4. Estimation of Tonnage and grade of each block of cutoff grade

5. Mapping of recoverable grade distribution plans by level or bench in

mine.

Weighting Methods

In brief, the geostatistical method requires a modern prospecting and exploration

method which heavily dependent on the digital computer as a basic tool in all stages of

the process.

Geophysical survey: The computer record, store, and analyze data ,then solve the

complex equation with a confidential result.

Sample and geological mapping: Given a helpful data including mapping of

topography, drill holes sample, surface layout, and other geologic formation.

Scheduling and planning: Cash flow and role of expenses in extraction.

Economic decision: Risk analysis data…

Feasibility study and Production rate

The production rate is played as an important role for business interest.

Somehow, we can make a calculation of production rate.

Gross value graded recovery price conversion facto

The profit: gross value - cost

costCutoff grade:

price recovery

III. Shovel Selection

What is Shovel Section??

Shovel Selection is a technological equipment and technical processes involved in shovels and

excavators in open pit and underground mine operations.

Mining Shovel is very

importance Step of mining

methods .

Let’s see the Example

For example: Ore production at Bingham Canyon is approximately

100,000 metric tons per day. With a waste-to-ore stripping ratio of 3:1, this

calls for drilling, blasting, and removing an average of 400,000 tons of

material per day, using power shovels with 5 to 20 m3 capacity dippers, rail

cars of 65 to 80 metric-ton capacity, and trucks designed to haul 60 to 140

metric tons of ore and rock. Shovels of this size require a bench at least 30

m wide. Heights of bench faces range from 4 to 8 m in weak rock and from

15 to 20 m in moderately strong rock.

TYPES OF SHOVELS

There are 2 types of shovels: 2.1. Electric rope

shovels: a bucket

capacities ranging from

20 m3 to over 100 m3,

raise and lower the

bucket using large

cables attached to

powerful electric

motors. With a 100 m3

shovel, it can fill a 300

ton haul truck in three

passes every 80

seconds.

TYPES OF SHOVELS

Hydraulic shovels

have a similar

capacity range, but

use hydraulics and

a forward or

backhoe loading

motion to dig into

the ore being

excavated.

Shovel’s dumping radius becomes as follows:

𝑅𝑠𝑑 = 𝑅𝑠 +𝐹𝑐2 Where: 𝑅𝑠 : Shovel’s reach

𝐹𝑐 : Width across both crawlers ( m )

The shovel’s reach can be radius calculated with following parameters.

𝑅𝑆 =1

tan𝜃𝑓𝐻 +

𝑊

4tan𝜃 − 𝑇

ℎ = 𝑅𝑆. tan𝜃 = 𝑓𝐻 +𝑊

4tan𝜃 − 𝑇

H: Cutting height ( m )

W: Span of dumping pile ( m )

F: Swell factor ( - )

T: Thickness of coal seam ( m )

𝜃: Angle of dumping pile ( rad )

IV. Belt Conveyer

There are many kinds of transportation system, such as:

- On the land

- On the sea

- At the air

Other transportation system for mining, for both Surface Mining and

Underground Mining is Belt Conveyor. Belt Conveyor is used for along time ago.

What is the Belt Conveyor?

Belt Conveyors Definition

A belt conveyor is a system of pulleys with a long loop of fabric or other material

stretched between them. Usually, at least one of the pulleys is motorized to pull the belt

along with it. They are used to conveniently move heavy objects from one part of

processing facility to another. Moving belt that transports materials or packages from one

place to another.

A belt Conveyor is one type of Conveyor.

Conveyors

Conveyor Systems for Mining

Conveyor Systems are built for a wide variety of surface mining applications

and are designed specifically for the unique geology and characteristics at each mine.

When determining design requirements for surface belt systems applications, the

following criteria are used for each customized solution, ensuring the best fit for your

mining needs.

Surface Conveyor System Design Criteria:

•Profile •Distance •Material Characteristics

•Tonnage •Capacity required • Preferred Speed (Optional)

Conveyor Systems for Mining

Belt conveyors are high-capacity, reliable transportation systems for mined

material. They represent the primary of intermediate haulage in most today’s

underground mines, and have gained acceptance for main-line haulage. Developments

in overland belt systems have also extended their influence to surface facilities. The

major components of belt-conveyor system are the belt, terminal pulleys, idlers ( the

cylindrical metal rollers that support the belt), support structure, take up ( tensioning )

device, motor and drive assemblies, and numerous protection devices.

Belt conveyors for Surface Mining

Belt conveyors for Underground Mining

See the Figure

Fig. 1

Fig. 2

Fig. 3

Belt Width and Speed

The acceptable operating ranges for the widths and speeds of conveyor belts are

often interrelated; this is due to the face that an increase in belt speed can permit a

reduction in belt width for any given mined material to be conveyed. To determine the

minimum belt width required, information must be provided on the maximum size of the

lumps to be conveyed and whether or not the lumps are uniform in size.

For example, if run-of-mine coal ( lumps and fines together ) is to be used to

indicate a minimum belt width of 36 in. Note that a 60-in. belt would be required if the

lump were uniformly sized at 12 in.

Once a minimum belt width ( based upon maximum lump size ) has been

determined, the speed of the belt can be established.

Cross Section of Belt Conveyor

Fig. 4

B: Belt width ( mm/ m )

b: 0.9B – 50 mm

L: B/3

: Ttroughing idlers angle

: Surcharge angle

h: Elevation change

Cross section area, A (m2

𝐴 = 𝐶0.9𝐵 − 50𝑚𝑚

1000

2

Table. Fig. 3 Constant for estimating cross section area, A, against surcharge angle,

5𝑜 10𝑜 15𝑜 20𝑜 30𝑜

C 0.0819 0.0963 0.1111 0.125 0.154

The transportation rate howmuch the voloum is transprted per hour = Production rate𝑄𝑡 (ton/h) = Production rate

Thus, the transportation rate, 𝑄𝑡 (ton/h) can be obtained from cross section area A (m2),

and its accompanying average belt speed 𝜈𝐵(m/min), material density, 𝜌 and conveyer

efficiency, 𝜂.

Rock 𝜌 = 1.8 ton/m3 , Coal 𝜌 = 0.8 ton/m3

𝑄𝑡 = 𝜂𝜌𝐴. 60𝜈𝐵

𝑡𝑜 𝑛 𝑚3

Belt Tension

A belt conveyor can be used for transporting mined material not only along the

horizontal but also along a change in grade. The power to move the belt is supplied by

the motor through a drive pulley. The maximum tension developed in the belt is the sum

of the following:

(1) tension to overcome the friction of the empty belt and the conveyor components that

come in contact with the empty belt

(2) tension to overcome the friction of the load

(3) tension to raise or lower the load and belt through elevation changes

Belt Tension

A belt conveyor system is one of many types of conveyor systems. A belt

conveyor system consists of two or more pulleys (sometimes referred to as drums):

1. with an endless loop of carrying medium

2. the conveyor belt that rotates about them. One or both of the pulleys are

powered, moving the belt and the material on the belt forward.

There are 2 types of the pulleys:

1. The powered pulley (the drive pulley )

2. The unpowered pulley (the idler pulley )

Belt Tension

Point of contact between a power transmission belt and its pulley. A conveyor belt

uses a wide belt and pulleys and is supported by rollers or a flat pan along its path.

Utilization

There are two main industrial classes of belt conveyors;

1. Used to transport large volumes of resources and agricultural materials, such as

grain, salt, coal, ore, sand, overburden and more.

2. Handled those moving boxes along inside a factory and bulk material.

Conclusion of Conveyor

In designing belt-conveyor system, mining engineers are concerned primarily

with calculating the necessary belt tension, take up force ( if necessary ), idler spacing,

and required motor horsepower. More detailed design information, such as belt width,

speed, and construction, can be determined from manufacture’s handbooks, of which

there are many. The following sections outline the design procedure for the calculation

mentioned previously.

V. Truck Haulage

Bulldozer

Bulldozers are used extensively in surface mining for zoning material

for short distance under difficult conditions

w

Bulldozer• Production rate Q (m3 /h)

• Empirical equation to estimate 𝑞𝐵base on blade size 𝑊𝐻

where

𝑊: Blade width (m) ; 𝑞𝐵: theoretical swelled dozing volume/cycle (=𝑓𝑞)(m3)

𝐻 : Blade height (m/min) ; 𝑞0: In-situ volume/cycle (m3)

𝐿 : One way distance (m) ; 𝑓 : Swelling factor (-)

𝑣 : Forward velocity (m/s) ; 𝜂 : Efficiency (-)

𝑣′: Backward velocity(m/s) ; 𝜉 : Operating factor depend on surface condition (-)

𝑇𝑔: Gear change time (s) ;𝜉𝐷 : Dozing factor depend on surface slope (-)

𝑇𝐶: Cycle time (s)

𝑇𝐶 =𝐿

𝑣+

𝐿

𝑣′+ 𝑇𝑔

𝑄 = 𝜂𝑞𝐵 × 𝜉

𝑇𝐶 3600= 𝜂

𝑞0 × 𝑓 × 𝜉 ⋅ 𝜉𝐷 𝑇𝐶 3600

𝑞𝐵 = 𝑓𝑞0 = 0.694 ×𝑊𝐻2

Bulldozer• Drawbar Pull

Where

𝑇 : Drawbar pull (N)

𝜇 : Pull coefficient ( friction factor) (=0.6- 0.9)

𝑀𝐵 : Bulldozer weight (ton)

𝑔 : Gravitational acceleration (=9.8 m/s2 )

• Dozing power

Where

𝑇 : Drawbar pull (N)

𝑉 : Pull velocity (m/s)

𝑃 : Pull power (W)

𝑇 = 𝜇 ⋅ 1000𝑀𝐵𝑔 𝑁

𝑃 = 𝑇 ⋅ 𝑣

Bulldozer• Wheel scrapers are used in surface coal mining for topsoil removal, road building

where

𝑄0: In-situ cutting volume (m3)

𝑄𝑠 : Filling volume (m3)

𝑞𝐵 : Bowl size (m3)

𝑓𝐶 : Swell factor by cutting (-)

𝑓𝑓 : Swell factor by filling (-)

𝜂0: Opening efficiency (-)

𝐾 : Bowl/Hopper fill factor (-)

𝑇𝐶: Cycle time (s)

𝑇𝑔 : Gear change time(s)

𝑄0 = 𝜂𝐾𝑞𝐵 × 3600

𝑇𝐶

1

𝑓𝐶; 𝑄𝑠 = 𝜂0

𝐾𝑞𝐵 × 3600

𝑇𝐶𝑓𝑓

𝑇𝐶 =𝐿𝐷

𝑣𝐷+

𝐿𝐻

𝑣𝐻+

𝐿𝑆𝑣𝑆

+𝐿𝑅

𝑣𝑅+ 𝑇𝑔

Bucket Wheel Excavator, BWE

BWE are continuous cutting machines for soft to semi hard materials like

clay, sand, gravel, marl and their blending as well as lignite and hard coal

Production rate of Bucket Wheel Excavator, BWE

BWE in-situ cutting volume rate and max. transportation volume rate are expressed by

Where

𝑸𝟎 : in-situ cutting volume rate (m3/hr)

𝑸𝑻𝑯: Max. transportation volume rate (m3/hr)

𝜼𝟎 : Operating efficiency (-)

𝑲𝑩 : Bucket fill factor (-)

𝑽𝑩 : Bucket volume (m3)

𝒇 : Swell factor (-)

𝒛 : Number of buckets on wheel (-)

𝒏 : Rotational speed per minute(1/min=rpm)

𝑸𝟎 = 𝜼𝟎

𝑲𝑩 ⋅ 𝑽𝑩 ⋅ 𝒛 ⋅ 𝒏

𝒇× 𝟔𝟎; 𝑸𝑻𝑯 =

𝒇𝑸𝟎

𝜼𝟎

VI. Reference

1. Howard L. Hartman & J.M Mutmansky: Introductory Mining Engineering 2002.

2. Website:

https://mining.cat.com/products/power-generation

http://technology.infomine.com/reviews/Conveyors/welcome.asp?view=full

http://technology.infomine.com/reviews/Shovels/welcome.asp?view=full#types

3. Google Images

4. Lan.C Runge : Mining Economic and Strategies

Conclusion

Question and Answer

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