1. MINE ENGINEERING
PRACTICE PROJECT
2015
Inefficiency of the load and haul process at Dorstfontein
mine which impacts the production outputs and profitability
Lawrence Tjale

2. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Scope and Objectives
Project Justification and Background:
Eqstra is an integrated leasing and capital equipment group, which also offers value-added services
to their customers through their three divisions - Fleet Management and Logistics, Industrial
Equipment and Contract Mining( MCC) and Plant Rental.
The mining process consists of:
 Drilling
o The process of sinking a hole into the earth to place the explosive material in.
 Blasting
o The process of placing the explosive material into the drilled hole and igniting it
 Loading
o The process of collecting the raw ore and placing it into the load bin of a dump truck
by using an excavator
 Hauling
o The process of transferring the raw ore from blast site to dump site
 Dumping
o The process of unloading the raw ore from the dump truck
From a capital expenditure and labour perspective, the load and haul require the greatest capital
investment; hence, the project will focus on this area.
Dorstfontein is currently one of three soft rock mine sites the MCC group is mining in. Currently there
are other initiatives to improve the other two sites, hence the reason I chose Dorstfontein.
Project Objectives:
 Define Dorstfontein tender and industry standards
 Identify actual production output
 Determine the difference between the standards and actual
 Identify reasons for the difference between the standards and actual
 Determine impact of difference between the standards and actual
 Identify possible solutions and recommendations
Exclusions from the project scope
 The actual implementation of these recommendations and the timeline process will be
excluded from this Project.

3. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Project Process:
Deliverable Deadline
Final Scope Completed 04 May 2015
Research Defined 13 May 2015
Research Complete 08 June 2015
Results 10 June 2015
Analysis of results & Recommendations 11 August
Draft Report 21 September 2015
Final Report Hand in 28 September 2015

4. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Coal Mining within South Africa
Mining is one of the most lucrative—and destructive—industries on earth.
China and the United States the greatest contributors globally with respect to coal production and coal
consumption with the likes of Russia, Australia Indonesia and Colombia competing with regard to
global export volumes.
South Africa is also viewed as being a significant contributor to the global coal market due to its
relatively low cost of production; it has the world’s largest coal export terminal and is positioned
conveniently between Atlantic and Pacific coal markets. It is a potential swing producer, able to export
competitively to either Europe or the East. (Eberhard, 2011)
The BP Statistical Review Of World Energy 2015 (BP, 2015) stated that South Africa held 30,156
million tonnes of total proven coal reserves by the end of the 2014 - 2015 period, of which 147.7
million tonnes was mined making South Africa the sixth largest holder of coal in the world (Coal,
2014).
89.4 million Tonnes of coal was consumed by South African Industry over this same period.
The coal reserves held in South Africa constitute more than a third of all coal reserves found within
the Southern Hemisphere and are the main source of energy supply to South Africa (Schmidt, 2010)
Fifty one percent of South African coal mining is done underground, the remaining 49 percent being
produced by open-cast methods (Energy, 2015)
As the country’s second largest earner in terms of the value of total sales after gold, coal provides
6.1% of the country’s total merchandise exports. By international standards, South Africa's coal
deposits are relatively shallow with thick seams, which make them easier and, usually, cheaper to
mine.
The Figure below supplies an overview of South Africa’s coal deposits in relation to the globe
Figure 1

5. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Challenges experienced within the South African context
Open-cast mining operations utilise haul trucks to transport the excavated cubic dirt or ore (cubes)
from one area to the next and are therefore designed to carry significant loads during each trip.
Figure 2 A CAT 785 Dump Truck and a Liebherr 9350 Excavator
This may seem to be a simple task. However there are numerous challenges that need to be
overcome to ensure that the haul process proceeds as smoothly and efficiently as possible. By
overcoming these challenges the mine operation will experience a significant increase in revenue as
either volume of cubes transported per hour will be increased or fewer machines would be utilised to
achieve the necessary outcomes.

6. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Challenges
The following challenges will be focussed on within the open cast mining sphere due to their
impact on the case scope:
 Weight Distribution and Transport
o Load placement in the dump truck bin
 Haul Road Traffic and Design
o The dump trucks operating surface
 Benches and Blasting
o The operating surface of the Excavator and the preparation thereof
Challenge 1: Weight Distribution and Transport
Whilst the haul trucks are designed to carry a predetermined amount of mass and volume, the cubes
of dirt or raw ore that are dumped into each truck will differ with each load cycle of the excavator.
Elliot Duff (Duff, 2004) explains how mining operations could leverage from various technologies to
improve the estimated tonnages and volumes within the load bin of the haul trucks. Density scanning
lasers (Cezary Toś, 2007) `mounted 5 m above the truck can measure the weight and volume of the
load and the data stored to be processed at a later time.
This data may range from: distribution, profile and fragmentations of the ores from each of the load’s
blast processes. This type of production monitoring will afford the mining operation an additional tool
of analysis to determine each truck’s load with a net result in increasing productivity.
Duff again advises that there are two ways in which productivity is to be improved:
 Reschedule haul trucks
 Re-evaluation of tray (load bin) designs
“Reschedule trucks”
Mining operations utilise a variety of mining equipment and it is critical that the equipment utilised is of
the best fit for the job on hand for each operation.
By rescheduling the best-fit haul truck to the type of material it will be transporting, the tonnage and
cubic volume transported per vehicle trip can be increased. This would furthermore result in the haul
vehicles requiring less maintenance per operational hour and decreasing the operational expenditure
per load cycle.

7. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
“Comparison of tray (load bin) designs”
Raw ores mined within each mining operation vary in structure, volume and weight and it is critical
that the correct tray or load bin be utilised, fitting not only the mining operation but also the raw ore
composition.
As load bins of each haul truck are designed to carry specific material compositions the mining
operation should monitor the effects on the load bins which have been used by the haul truck, as an
incorrect fit would shorten the life span of the tray.
Challenge 2: Haul Road Traffic and Road Haul Design
A study by Andrew Chapman from the Queens University (Chapman, 2012) showed how haul road
traffic is increasingly becoming an area of concern for mine operators. Due to the time spent by mine
operators in traffic the mining operation suffers a considerable decrease in cubic output as
productivity is slowed.
Furthermore, each haul truck is generally filled to its maximum haul capacity and this raw ore
becomes stationary in the haul process should haul traffic not be managed. Due to differing materials
having varying densities, shape and volume the number of units each haul truck can transport is
variable and this affects the operation.
During the haul phase there is a great emphasis placed on the completion of the haul cycle as fast
and efficiently as possible. Any decrease in the time taken for each haul truck to complete its haul
cycle will have a significant impact on the productivity of the mining operation and ultimately on the
revenue of the operation.
The mine haul road network and infrastructure is a vital and highly critical component of the
production process and a poorly designed network and surface carry a significant portion of costs on
a mine’s productivity. The provision for and creation of a well maintained haul road enables the
machinery to operate more efficiently and in a safer environment.

8. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
RJ Thompson (Thompson, 2011) confirms this requirement of an integrated design approach.
This approach is referenced to:
 Reduce traffic hazards and provide for safer driving conditions
 Reduce operational costs
 Improve cycle times
 Less maintenance costs
 Improvement on rim and tyre life, drive trains and suspensions
Thompson confirms that many concepts from general highway engineering can be adapted from and
applied when implementing this approach on the design, construction and maintenance phases. It
should however be noted that there are significant differences between the two design approaches
due to applied loads, traffic volumes and costs. As such the design is basically flawed should all
factors not be accounted for within the integrated design approach.
Impacts to be expected are amongst others:
 Rolling resistance increases, translating into
 Equipment downtime
 Increased maintenance costs (machinery and the road itself)
Challenge 3: Bench creation and Bench heights
Blasting actions result in the addition of air molecules into the compacted earth resulting in the earth
taking up more volume. This addition creates what is referred to as heave, resulting in additional ore
and ground required to be moved which is not accounted for within the initial surveying analysis.
This heave creates an area of operation not suitable for the excavators to operate on due to it’s
unstable nature and should firstly be levelled to facilitate the operation of the excavators.
Bench heights (A in Figure 4) (the vertical distance between the each horizontal level of the pit
(Kennedy, 1990) are determined by taking into account the excavators stick length (C in Figure 4). If
the stick is 5 meters the bench should also be approximately 5 meters. This will enable the bucket to
be filled more easily as the backhoe is designed to have maximum force in a digging motion when
using the boom cylinders to assist with the lift and breakout force (stick cylinders).

9. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Figure 3 will assist in explanation of the various excavator components:
Figure 3
If the bench is too low the operator tries to fill but cannot use the boom function as desired or the
bucket will be only 50% full. The excavator operator must reload and reposition himself in the time
frame of the truck exchange. Time frame for exchange is approximately 40 seconds and should not
be exceeded. The excavator must be ready to load as soon as the truck is in place.
The following photos will explain digging better:
Figure 4
Legend:
A – Correct/good bench height
(A = B = C)
D – Good flat operating surface
Legend:
A – Boom
B - Stick
C – Boom cylinders

10. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Hossein, Marteza et al (Selection of practical bench height in open pit mining using a culti-criteria
decision making solution, 2010) showed that if there were two options for bench heights - a 10 meter
bench or a 12.5 meter bench - for an open pit mine, the calculations showed that the time used for the
load and haul process for the 12.5 meter bench was 33.33% faster than the 10m bench. This shows
that the optimum bench height used by a mine should be calculated based on the equipment
operating at that mine.

11. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
MCC Tender
MCC was awarded the Dorstfontein tender in February 2011. The Tender employs on average 29
persons who manage the following kit:
 1 x Liebherr 974 excavator
 1 x Liebherr 9350 excavator
 2 x Liebherr 984 excavators
 13 x CAT 777 dump trucks
 4 x CAT 785 dump trucks
 Assortment of support equipment including road graders, water trucks and dump trucks
The Net Book value of the equipment is R 359 million Rands as of August 2015
The team conducted a site visit to Dorstfontein mine in Mpumalanga to determine the current process
and identify the gaps that exist.
The below highlights the various items focussed on as detailed in the project objectives, weighing up
the industry norms to site actuals:
Item Industry
Standards
Actual Practices Variance between Standard and
Practices
Bench preparation Flat surface Uneven, unstable 7.5min delay for Excavator to
prepare its work bench
Bench height 5m 5m Meets standards
Haul road quality Smooth surface Marked with
numerous
potholes
Vehicles unable to maintain a
constant speed and travel in a
straight line
Haul road gradient Smooth
constant grade,
not undulating
Uneven and
lacking
consistency. 13
degree incline
3 degree increase in incline, sudden
increase around corner from gradual
to steep requiring downshift and
decrease in average rolling speed
Truck fill factor 40bcm 36bcm 4bcm per load lost due to inefficient
loading

12. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Recommendations
The Practices as detailed above support the research provided highlighting the critical nature that the
haul roads play in the effective operation of the mine.
Based on the variances found between the Industry Standards and actual outputs from Dorstfontein,
the team have found that the most sustainable route to achieve our predetermined scope objectives
would be a focus on two key items:
1. The upgrade of the current road infrastructure, the future design and maintenance thereof
going forward
2. The view to ensure dump trucks are filled to their maximum capacity with each load cycle
Each project will be implemented as per the below structure:
1. Road haul upgrade
The team propose the upgrade of the current road infrastructure by focusing on the incline
and gradient increase found at turn 1 (refer to attached Dorstfontein schematic) leading from
West to the incline moving South.
Loads transported will be dumped systematically at this point rather than at the dumping
ground at section 1 (refer to attached Dorstfontein schematic – Appendix 1)
Each load will be levelled out with a CAT D10 Dozer already being utilised on site for this
same function at section 1.
Once levelled, a CAT 14M Grader will be utilised to smooth the surface level to an acceptable
operating surface.
Both additional machinery items will carry a zero running cost addition as they are already
accounted for in the monthly budgeting for the very roles they will be required for.
Once completed all current haul roads will be upgraded with the CAT D10 grader, ensuring all
potholes are filled and the surface is kept at a constantly smooth surface.
The implementation of this recommendation would result in an efficiency increase of 15%
based on discussions held by senior MCC Plant and Engineering Managers.

13. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
2. Load capacity management
Each excavator is to be allocated a dedicated supervisor
Their role is to ensure each dump truck is loaded to an optimal level rather than the current
80% capacity as highlighted in the site visit Practices.
Each supervisor will further be managed by a Senior Supervisor monitoring each load from
the central view point. This will ensure the optimal load of each dump truck, increasing that
the cubic transport per load be increased by 15%, allowing for a 5% variable to 100%
capacity

14. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Business Case
The financial information provided herewith has been supplied courtesy of MCC Finance Department
It should be noted that all values quoted are subject to both the Engineering and Production
Departments of MCC Dorstfontein remaining within their allotted budgets and parameters
All costs are determined as a multiplier of an hourly rate
The below table highlights briefly the following, all supporting figures are supplied as Appendix 2
 Current monthly Operational Expenditure
 Proposal 1 - Impact on profitability when the haul road upgrade is actioned
 Proposal 2 - Impact on profitability when the load capacity optimisation is implemented
 Combination - Impact on profitability when both Proposal 1 and Proposal 2 are implemented
Current Proposal 1 Proposal 2 Combination
Engineering R5.8m R4.9m R5.2m R4.6m
Depreciation R2.0m R1.8m R1.8m R1.6m
Interest R1.4m R1.2m R1.3m R1.1m
Insurance R29k R25k R26k R23k
Average
Monthly Cost
R9.2m R7.9m R8.4m R7.3m
Average
Monthly
Saving
R1.3m R794k R1.9m
Saving vs actual Proposal 1 Proposal 2 Combination
Engineering 14% 9% 21%
Depreciation 12% 8% 21%
Interest 14% 9% 21%
Insurance 14% 9% 21%
Total Monthly Saving 14% 9% 21%

15. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Bibliography
A REVIEW ON EXISTINGOPENCASTCOALMININGMETHODS. Scott,B, et al. 2010. 2010, Journal of
MiningScience,Vol.46,No.3, 2010, p. 280.
BP. 2015. BP Statistical Review of World Energy 2015. London : Platts,2015.
Cezary Toś, Bogdan Wolski,LeszekZielina.2007. OPTIMIZATION OFLASERSCANNINGTECHNOLOGY
IN MONITORINGOFROCKANDNATURALGROUNDSURFACE. Cracow : PolishMinistryof Science and
HigherEducation,2007.
Chapman, Andrew.2012. A FieldStudyonHaul Time VariabilityinOpenPitMines. Qspace. [Online]
2012. https://qspace.library.queensu.ca/handle/1974/7410.
Coal, Universal.2014. Universal Coal PLC. UniversalCoalPLC. [Online] 2014. [Cited:June 10,2015.]
http://www.universalcoal.com/our-projects/coal-mining-in-south-africa/~.
Duff, Elliot.2004. AutomatedVolume Estimationof Haul-TruckLoads. CSIROManufacturing Science
and Technology. 2004, Vol.2.
Eberhard, Anton. 2011. The Futureof South African Coal:. Stanford : StanfordUniversity,2011.
Energy, RepublicofSouth Africa Department of. 2015. Coal Resources. Republicof South Africa
Departmentof Energy. [Online] 2015. http://www.energy.gov.za/files/coal_frame.html.
Jai, Shreya. 2015. Economyand Policy. BusinessStandard. [Online] August27,2015.
http://www.business-standard.com/article/economy-policy/global-coal-price-on-the-downslide-
115082700011_1.html.
Kennedy,Bruce A. 1990. Surface Mining,SecondEdition. SurfaceMining,Second Edition. s.l. :SME,
1990, 1990.
Mitra, R and Saydam, S. 2012. Surfacecoal mining methodsin Australia. 2012.
Schmidt, Stephan.2010. Coaldepositsof South Africa - the futureof coal. Freiberg:Institute for
Geology,Technische UniversitätBergakademie,2010.
Selection of practical bench heightin open pit mining using a culti-criteria decision making solution.
Soltanmohammadi,Hossein,et al. 2010. June 2010, GeologyandMiningResearchVol.2,p.55.
Thompson, Roger. 2011. Mine haul road design,constructionandmaintenance management.[book
auth.] PeterDarling. SMEMining Engineering Handbook. Lyettleton,Colorado :s.n.,2011.

16. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Annexures
Annexure 1: Schematic representation of MCC Dorstfontein Mine
Annexure 2: Financial documentation as support to Business Case
Annexure 1

17. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Current operational expense figures from MCC Dorstfontein
The operational variable costing matrix is supplied as per the below rate card:
Model Unit
Depreciation
rate
Eng Plant rate
CAT 777 Hour 282.57 574.88
CAT 785 Hour 221.48 942.08
CAT 773 Hour 18.74 357.70
The operational fixed costing matrix is supplied as per the below rate card:
Model Fleet Unit Interest rate Interest Insurance rate Insurance
CAT 777 14 Month 47 267.02 661 738.29 928.51 12 999.14
CAT 785 10 Month 76 305.96 763 059.57 1 563.66 15 636.57
CAT 773 Month 23 434.99 - 463.55 -
Total monthly expenses - R 9,210,429.12
Truck
Loads per
hour
bcm per
load
Tender
bcm per
hour
Forecast bcm per
hour
Units Availability Utilisation Hours worked
TOTAL bcm for
month
CAT 785 5.8 38 221 10 80% 70% 3 405 751 841
CAT 777 4.1 35 144 14 80% 65% 4 426 635 165
CAT 773 4.4 13 57 - 85% 0% - -
1 387 007
Truck
Total
Units
Hours
Operation
Depreciation
Rate
Engineering
Rate
Interest Rate
Insurance
Rate
Monthly
Depreciation
Monthly
Engineering
Monthly
Interest
Monthly
Insurance
Total Montlhy Cost
CAT 785 10 3405 R 221.48 R 942.08 R 76 305.96 R 1 563.66 R 754 139.40 R 3 207 782.40 R 763 059.60 R 15 636.60 R 4 740 618.00
CAT 777 14 4426 R 282.57 R 574.88 R 47 267.02 R 928.51 R 1 250 654.82 R 2 544 418.88 R 661 738.28 R 12 999.14 R 4 469 811.12
R 9 210 429.12
Annexure 2

18. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Proposal 1: Road haul upgrade
By improving the haul roads, the team propose a 15% improvement in the total loads per hour.
The below outputs will be achieved:
The net result amounts to the removal of 2 CAT 785’s and 1 CAT 777’s from the fleet.
The financial impact is a net cost savings of R 1,063,338.56 per month
Truck
Loads per
hour
bcm per
load
Tender
bcm per
hour
Forecast bcm per
hour
Units Availability Utilisation Hours worked
TOTAL bcm for
month
CAT 785 6.7 38 254 8 80% 70% 2 724 691 694
CAT 777 4.7 35 165 13 80% 65% 4 110 678 266
CAT 773 4.4 13 57 - 85% 0% - -
1 369 960
Truck
Total
Units
Hours
Operation
Depreciation
Rate
Engineering
Rate
Interest Rate
Insurance
Rate
Monthly
Depreciation
Monthly
Engineering
Monthly
Interest
Monthly
Insurance
Total Montlhy Cost
CAT 785 8 2724 R 221.48 R 942.08 R 76 305.96 R 1 563.66 R 603 311.52 R 2 566 225.92 R 610 447.68 R 12 509.28 R 3 792 494.40
CAT 777 13 4110 R 282.57 R 574.88 R 47 267.02 R 928.51 R 1 161 362.70 R 2 362 756.80 R 614 471.26 R 12 070.63 R 4 150 661.39
R 7 943 155.79

19. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Proposal 2: Load capacity management
By improving the load volumes by 10%, the below outputs will be achieved
The net result amounts to the removal of 1 CAT 785’s and 1 CAT 777 from the fleet
The financial impact is a net cost savings of R 793,793.29 per month
Truck
Loads per
hour
bcm per
load
Tender
bcm per
hour
Forecast bcm per
hour
Units Availability Utilisation Hours worked
TOTAL bcm for
month
CAT 785 5.8 42 243 9 80% 70% 3 064 744 323
CAT 777 4.1 39 158 13 80% 65% 4 110 648 776
CAT 773 4.4 13 57 - 85% 0% - -
1 393 099
Truck
Total
Units
Hours
Operation
Depreciation
Rate
Engineering
Rate
Interest Rate
Insurance
Rate
Monthly
Depreciation
Monthly
Engineering
Monthly
Interest
Monthly
Insurance
Total Montlhy Cost
CAT 785 9 3064 R 221.48 R 942.08 R 76 305.96 R 1 563.66 R 678 614.72 R 2 886 533.12 R 686 753.64 R 14 072.94 R 4 265 974.42
CAT 777 13 4110 R 282.57 R 574.88 R 47 267.02 R 928.51 R 1 161 362.70 R 2 362 756.80 R 614 471.26 R 12 070.63 R 4 150 661.39
R 8 416 635.81

20. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678
Combination - By implementing both recommendations, the below outputs will be achieved
By combing both proposed changes, the below outputs will be achieved
The net result amounts to the removal of 3 CAT 785’s and 2 CAT 777’s from the fleet
The financial impact is a net cost savings of R 1,905,572.74 per month
The financial impact is a net cost savings of R 1,905,572.74 per month
Trucks
Truck
Loads per
hour
bcm per
load
Tender
bcm per
Forecast bcm per
hour
Units Availability Utilisation Hours worked
TOTAL bcm for
month
CAT 785 6.7 42 279 8 80% 70% 2 724 760 863
CAT 777 4.7 39 182 11 80% 65% 3 478 631 309
CAT 773 4.4 13 57 - 85% 0% - -
1 392 172
Truck
Total
Units
Hours
Operation
Depreciation
Rate
Engineering
Rate
Interest Rate
Insurance
Rate
Monthly
Depreciation
Monthly
Engineering
Monthly
Interest
Monthly
Insurance
Total Montlhy Cost
CAT 785 8 2724 R 221.48 R 942.08 R 76 305.96 R 1 563.66 R 603 311.52 R 2 566 225.92 R 610 447.68 R 12 509.28 R 3 792 494.40
CAT 777 11 3478 R 282.57 R 574.88 R 47 267.02 R 928.51 R 982 778.46 R 1 999 432.64 R 519 937.22 R 10 213.61 R 3 512 361.93
R 7 304 856.33

21. MINE ENGINEERING PRACTICE PROJECT 2015 LAWRENCE TJALE 36927678