PMY 311 - Surface Mining Module 4 - Haulers Study Guide

UNIVERSITEIT VAN PRETORIA - PMY 311 - SURFACE MINING

  • Faculty of Engineering, Built Environment and Information Technology

  • Module 4 - Haulers

  • Instructor: Dr Sezer Uludag

Course Content

  • Overview of primary topics:

    • Haulers and haul roads

    • Learning outcomes focused on:

      • Knowledge and understanding of truck selection factors

      • Truck specifications and types

      • Tyre selection for haul trucks

      • Design and specifications of haul roads

      • Trolley assist and allocation systems

      • Estimation and calculation of truck productivity

      • Application of Earned Value Management (EVM) and Gross Vehicle Mass (GVM)

Truck Types and Specifications

  • Articulated Dump Trucks

    • Manufacturers: Bell, Hitachi

    • Example models:

      • 830E Bell

      • 830E Bell (repeat)

  • Motorized Wheel Trucks

    • Example: GEB25 AC

  • Other Models

    • Komatsu models including 101, 102, and 100-MAY'S

Comparison of Haul Trucks

  • Mine Haul Trucks:

    • Types based on axle configurations:

      • 2 axle vs. 3 axle

    • Discussion points:

      • Pros and cons of 2 axles versus 3 axles

      • Double tyre advantages and disadvantages vs. single tyre

  • General Characteristics:

    • Smaller trucks are mechanically driven

    • Larger trucks may use electric wheel motors with a capacity of over 130 tonnes.

Material Basics in Surface Mining

  • Concept of Swell:

    • Disturbance increases volume (30% swell, hence multiply by 1.3)

    • Relationship between loose material density, swell factors, and load calculations.

  • Definitions:

    • Dry weight density: $2.0 ext{ t/m}^3$

    • BCM t/m³ = LCM t/m³

  • Significance of loose volume and density:

    • Crucial for calculating load and haul requirements and overall fleet sizing,

    • Understanding loading tool bucket ratings in loose m² volume and haul truck ratings in tonne payload limits.

Density and Weight Calculations

  • Question Example: Given the density of shale is 1.8 and a swell of 30%, calculate LCM.

  • Understanding metric tonne difference:

    • Comparison of ton, long ton, and short ton:

      • Metric ton = 1,000 kg,

      • 1 short ton = 2,000 lbs = 0.9072 metric ton,

      • 1 long ton = 2,240 lbs = 1.01605 metric ton.

Comparative Analysis for Truck Types

  • Load to vehicle mass ratio: HEVM, BDT

    • TRUCK TYPES:

      • Rear Dump Truck load: 1.45

      • Bottom Dump Truck load: 1.70

    • Propulsions to Vehicle Mass Ratio:

      • Rear dump: $9.5 ext{kW/t}$; Bottom dump: $7.6 ext{kW/t}$

    • Design Metrics:

      • Turn radius for 2 axles is $1.2 imes ext{length}$; for 3 axles $0.63 imes ext{length}$

      • Bucket resistance varies significantly.

Factors for Truck Selection

  • Key considerations include:

    • Characteristics of rock and ore

    • Transport route: grade, length, curves

    • Space for maneuvering

    • Dump conditions and design

    • Surface conditions of mine roads

    • Compatibility with loaders and current fleet configurations

    • Mine's production output requirements (both ore and waste tonnage).

Payload and Operational Efficiency

  • Discussed issues with 'carry back' of dead material affecting payload distribution.

  • Tyres: their high costs and selection criteria based on weight dynamics:

    • Maximum weight per tyre ranges between 65-70t + 20% dynamic load totaling around R550,000 with a lifespan of approximately 6000 hours.

Understanding TKPH Rating

  • TKPH:

    • Stands for Tonne-Kilometres Per Hour.

    • Critical for each tyre specification regarding load capacity versus heat generation.

    • Calculated as (Tyre Load) x (Average Speed).

    • Varied methods among tyre manufacturers, with implications for the tyre life and operational cost-effectiveness.

TKPH Application in Trucks

  • Example Calculation:

    • Average load: $12,000 ext{ kg}$ or $12 ext{ tonnes}$; average speed: $26.25 ext{ km/h}$; calculating TKPH yields $315 ext{ TKPH}$.

  • Implications for tyre selection based on calculated TKPH must exceed operational TKPH for safety and efficiency.

Haul Road Design Essentials

  • Key facets of haul road productivity:

    • Cost-saving for transport and mining operations.

    • Required load-bearing capabilities of the road surface (50-90t ESWL).

    • Cost estimates for haul road construction can vary significantly between R300,000 to R1,500,000 per kilometer, emphasizing long-term planning and sustainability.

    • Maintenance management to ensure optimal functionality and cost efficiency over the lifetime of haul roads.

    • Core components:

      • Structural and functional design to support imposed loads

      • Maintenance frequency management for optimal costs.

Trolley Assist Systems

  • Application and operational benefits of trolley assist systems in mining:

    • Used to manage increasing transport costs as mines go deeper.

    • Significant contribution to reduction in operational costs, especially over longer distances and steep slopes.

    • Generating operational efficiencies such as fuel and time savings in hauling processes with potential capital requirements estimation detailed.