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World Mining – Future mass mining options under consideration 30 September 2014
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World Mining – Future mass mining options under consideration30 September 2014
WealthUnearthed
• Ideas presented are a result of the author’s direct involvement (in conjunction with industry technical leaders) in major international and collaborative research projects on mass mining methods and blasting: – International Caving Study (ICS)– The Mass Mining Technology (MMT)– Supercaves (2011 – 2014)– Hybrid Stress Blasting Model (HSBM)– The Next Generation Cave Mining (Phase 1 (2014)– Ultra-Deep open pit mining (conceptual study and workshops )
Illustrations and figures used have been sourced from ICS, MMT, Supercaves and The Next Generation Cave mining member companies and are therefore
acknowledged
DISCLAIMER
An observation
The mining industry is now moving rapidly into a new and potentially much higher risk investment territory…..……“easy” and “near surface” orebodies are being consumed
NOTE:
During this presentation, we need to also think of how “the new and potentially much higher risk investment territory” is likely going to impact on the drilling and blasting (explosives) industry”. Also what
are the opportunities?.
Depletion of near surface deposits and increasing discoveries of Deeper
Deposits generally with Lower average Grades but with very large mining
footprints (ranging from approx. 5 ha to just over 200 ha).
Increasing demand for production from Underground Mass Mining Sources
to supplement Surface Mass Mining Sources
Deposits in Stress and Temperatures (Geotechnical/Geothermal/?) much
higher than previous and current experience
Environmental constraints (License to Operate) and associated legislations
Stricter demands for better Energy and Water management or utilisation
Developing new mining projects under Capital Constraint
The mass mining industry must change
The Mining Industry “Drivers for Change”
MASS MINING
� Mass mining may be carried out either by:
− large open pits;
− bulk underground mining methods:
○ block and panel caving (BC/PC)
○ sublevel caving (SLC)
○ sublevel open stoping (SLOS)
○ Generally non-selective with production
rates of greater than 10,000 tpd
BUT: Can equally have economic, technical, safety and environmental risks that need to be properly managed.
To maintain profitability whilst minimising risk requires on-going R&D to address existing and new KNOWN –UNKNOWNS of cave mining.
Cave mining increasingly a method of choice to extract low grade massive ores profitably
Increased production from underground cave mining
(e.g. Copper, Molybdenum and Gold)
Increased use of automation (mainly trials and prototypes)
Intelligent mining (ITC)
Remote Centre Operations
Stricter adherence to License to Operate
MINING TRENDS: Since 2009
INCREASED UNDERGROUND
PRODUCTION IN THE NEXT
30 YEARS
(200 KTPD TO 500 KTPD)
INCREASED UNDERGROUND
PRODUCTION IN THE NEXT
30 YEARS
(200 KTPD TO 500 KTPD)
CODELCO CHILE
Automation and Remote Centre Operations
Future Mass Mining Options
Ultra deep pits
Transition
Deep and large footprint cave mines
In-situ mineral extraction
4.5 km
2.7 km
850 m deepFinal depth > 1km
Undercut levels approx.2 km below surface
Aim is to drill into the mineralised region at depth,
precondition ore and leach-out metal from
mineralized zone (recovering ~1-2% of ore mass and
leaving ~99% of gangue in place)
Next Generation Surface Mass Mining
Applying large scale open pit mining to depths equal and/or greater than 1000m and approaching 1800m as well as the ability to also mine up to a Gigatonne-per-year mining (ore and waste) from a single or multiple or linked group of open pit operations (BHP Billiton 2012)
Challenges and Opportunities
• Mine design and planning for mega-pits
• Drilling and blasting options (optimised fragmentation and liberation)
• Increased productivity via mega blasts
• Continuous and high productivity materials management system for the Giga-tonne per-annum open pit mining
• Waste rock management
• Selective mining “Grade engineering”
• Orebody geology in its broadest sense
If 5% of your material causes 50% of your downtime, the whole project is at risk. Courtesy of SKM
Ultra Deep Open pit mining options
Various Shovel – Truck Systems
Truckles operations
In-pit crushing and conveying systems (IPCC): fixed, semi-mobile, fully mobile
Combination of surface and underground material handling systems
Near to vertical final pit walls (slopes)
Steep conveyor systems
Mega-blasts
What constitutes “ULTRA-Deep Pits” and what percentage of the industry is likely
to mine such pits (i.e. Pits with depths greater than e.g. 1200m to 1800m) in the
next 10 to 15 years ?
How deep can current pits be mined effectively, safely and economically using
current practice and technology ?
At what point should transition to cave mining methods be considered i.e.
geotechnical, economic, environmental, technological, productivity ?
What unique issues are likely to be faced by the Ultra-deep pits ?
What are requirements of the future large scale and deep open pits also looking at
technical and material handling issues
What are the logistical issues likely to be faced (human, automation, interaction) ?
Key questions
HIGH CAPACITY & ULTRA DEEP OPEN PIT MINING
12
Main points to consider:
Slope angles and Mine Design
1. Geotechnical model.2. Stress distribution.3. Maximum wall heights.4. State of the art in control of slopes.5. Large push-backs and connectivity.
Material Handling
• Mine design as material handling system.• Reducing distance haulage.• Autonomous trucks• Trucks alone in the pit.• High angle straps.• Material pass Systems, tunnels and straps.• Crushers in the pit and / or underground.• Elevators.• Shovel / conveyor belt
Others Considerations
1. Suppliers are looking for partners to develop unproven technology.
2. Underground infrastructure development. (Eg caves for crushing room, etc.)
Types of deposits
1. Mass and low grade (ratio W / O low).2. Plant: Technology to process low grade
ores.
Implementation
1. Methodology tunneling (TBM, conventional)2. Prestripping
Anglo-American Copper
The next generation of cave mining
Gravity cave mining systems: grizzly and slusher layouts
Focus areas:
Caving of massive, low strength and usually low-grade ore bodies which produced fine fragmentation
Gravity and “Chimney” caving
Manual operations
Stability of small extraction layouts
Support of extraction levels
Rock mechanics
Dilution
1st GENERATION CAVE MININGPre- 1980
Example of focus areas:
Cave mining in strong ore rocks (primary rock) and at moderate depths
Alternation mining layouts (panel caving)
Mechanisation
New ground support concepts
Production efficiency utilising batch systems and current extraction level layouts e.g. Teniente and Herringbone
Rock mechanics and Numerical modelling
Increased safety
2nd Generation Cave Mining1980 to Current
Orebody knowledge (plus variability and uncertainties)
Rapid and safe access to deep orebodies (Rock cutting vs. drilling and blasting)
Rapid and Safe cave establishment (Rock cutting, long-rounds and rapid short round)
Continuous and automated production systems
New cave mining layouts for automated and continuous production)
Significantly reduced mining costs (CAPEX and OPEX)
Minimum environmental impacts (licence to operate)
Human capital
New generation cave mining operators, technicians, and engineers and management processes
Better integration between mining and processing (next generation Mine to Mill)
Risk and Safety
Focus areas (The Next Generation Cave Mining)
Vision of the Next Generation Cave Mining
Feasibility of machine mining
Mechanical Undercutting System
Drill and Blasting Undercutting
Chitombo, 2010
Peng, 1983Work area ahead of cutting front
Work area behind cutting front
CODELCO’SSupercaves
Comparisons
(approximations)
Current caving operations
Footprint ± 200m X 200mBlock heights ≤ 500mTonnages: 10,000 – 40,000 tpdUndercut level = < 1.5 km
± 500 drawpoints
SupercavesFootprint=± 2km x 2kmBlock heights ≥ 500m approaching 1000mTonnages 70,000 tpd approaching 160,000 tpd (single panel)Undercut levels = >1500m approaching 2000m1000 – 2000 drawpoints
20
1500m
To form an international mining industry collaboration (consortium) to fund, support and therefore accelerate the development of critical and high impact innovations as well as the underpinning knowledge (supporting research) needed to ultimately achieve the desired End-State (Vision 2018/2025)
To also collaboratively address and develop solutions to manage a number of the foreseen technical, economic and environmental challenges that the cave mining industry is likely to face henceforth and worldwide (known-unknowns).
The Goal (an industry perspective)
Benefits of electronic detonator blasting demonstrated
Fragmentation
Throw
Vibration control
Bulk delivery systems standard practice
Mine to Mill philosophy attempted but with mixed results
Little change in the bulk explosive product energy range
Little work tailoring blasting to different geology's. Tendency one size fits all at sites.
Much improved drilling technology (More accurate drilling)
MWD (not readily used for D&B design and optimisation)
Advancements in computer blast modelling (e.g. HSBM)
The drilling and explosives industry:The last 15 to 20 years
Geomechanical code
Detonation codesIdeal and non-
ideal
VixenBlo-Up
Modelling EngineDetonation
Fracturing
Fragmentation
Displacement
Near-field Damage
Rock and fragment Conditioning
Back of
detonation
driving zone
(sonic surface)
Shock front
End of
reaction
zone
Detonation modelling The rock breakage engine
The Hybrid Stress Blasting Model (HSBM)
Some OPPORTUNITIES FOR EXPLOSIVES COMPANIES
Rapid and safe development (long round drilling and blasting or short rounds)
Preconditioning to enhance caving (confined and/or unconfined blasting)
Sublevel caving blasting to improve fragmentation and recoveries
Ultra-deep pits – blasting for increased productivity
More effective wall control practices for the ultra-deep pits
Leaching- Blasting for increased leaching recoveries (in-situ and heap)
Fragmentation for alternative mills (e.g. HPGR)
Fragmentation for optimal ore/waste sorting or “Grade Engineering”
Truckles mining – controlled fragmentation for conveyors or IPCC
Wireless booster for increased blasting flexibility
Blast monitoring and sensors
PRECONDITIONING BY CONFINED BLASTING
Hole diameter 165mm
Hole length 150m
Charge length 130m
Charge weight ~3,285 Kg
Density Emulsion 1.18 g/cm3
VOD Emulsion >5,500 m/s
Stemming high strength plug
20m
Cure time stemming plug 72hr (minimum)
UCS stemming plug 50MPa (minimum)
Location initiation pointsEvery 8m along of explosive column
Initiation time Every point in the column are started simultaneously
PC1-S1
Lift 1
UCL level
EXT level
Hydrofracturing Level (5050mRL)
Finally
The Next Generation Mass Mining
….novel initiatives are being considered for the next generation of both underground and surface mass mining systems.
This in order to access and established mass mining methods much faster and safer than current, significantly reduce mining costs (CAPEX and OPEX), substantially increase productivity (continuous) while being cognisant of license to operate issues.
NEXT GENERATION MINERAL EXTRACTION: a more integrated mineral extraction system.
World Mining – Future mass mining options under consideration28 September 2014
Thank You