Large Open Pit Mine Slope Stability Project
Design Guidelines



Aims and Overview
The ideas outlined in literature concerning rock slope failure mechanisms and the appropriateness of different pit slope design approaches are diverse.

To overcome the uncertainties generated by this diversity, the project is preparing and publishing authoritative new generation pit slope design guidelines which will detail accepted practice for today’s practitioners.   The aims and objectives of the publication, titled Guidelines for Open Pit Slope Design, are to link innovative mining geomechanics research together with accepted practice highlighting:

what works best in different situations (and why);
what doesn’t (and why not); and
what is needed to satisfy accepted practice with respect to pit investigation, design, performance, and operation from the options available.

The project’s fundamental objective is to provide the slope design practitioner with sufficient armoury to ensure that if the slopes do fail there will be:

no loss of life;
no equipment damage;
no sustained loss of production; and
an ability to mine published reserves.

Chapter Outlines
Following the initial development of 12 chapters, the Guidelines for Open Pit Slope Design book has been re-structured into 14 chapters that follow the life of mine sequence from concept through to closure.

In order to help the practitioner deal with short comings in the investigation and design process, each chapter deliberately focuses on leading issues such as what data is required, how it should be processed and which analysis should be used.
The chapter contents are as follows:

Chapter 1: Fundamentals of Slope Design

Outlining the fundamentals associated with achieving a balanced design in terms of the expectations of the various stakeholders in the mining operation (owners, management, workforce and regulators), including:

  • the aims of pit slope design;
  • the framework, both corporate and regulatory, that control slope designs; and
  • the geotechnical requirements at each stage of project development, from the initial conceptual study through pre feasibility and feasibility to detailed design, operation, and mine closure.

Chapter 2: Field Data Collection

Outlining the availability and application of the mainstream technologies that are used to provide a functional engineering classification of the rock mass for slope design purposes.

Chapter 3: Geological Model

Linking the regional geology and the events that lead to the formation of the orebody to a mine-scale description of the nature (rock type, degree of weathering and alteration) and distribution of each geological unit on site.

Chapter 4: Structural Model

Describing the orientation, distribution and nature of; through-going faults at the regional, overall pit slope and inter-ramp scales, and lesser faults and joints (fabric) at the inter-ramp and bench scale.

Chapter 5: Rock Mass Model

Describing the engineering properties of the rock mass and its constituents, including:

  • the nature of the standard index and mechanical property tests that are used in rock slope engineering;
  • the properties of the mechanical defects in the rock mass, especially shear strength and the effect of surface roughness;
  • rock mass classification systems; and
  • current and newly developed means of assessing the strength of the rock mass.

Chapter 6: Hydrogeological Model

Describing how the presence of groundwater and the resulting pore water pressure may affect open pit design and performance, including:

  • discussion of groundwater hydrogeology and its implications for rock slope engineering in the mining industry;
  • a practical explanation of hydrogeology, including the concepts of fracture groundwater flow, how groundwater relates to pore pressures, and the relationship between total and effective stress;
  • a distinction between general mine dewatering and slope depressurisation; and
  • how a conceptual hydrogeological model is developed, including recharge to fractures, phreatic and piezometric surfaces, vertical and horizontal hydraulic gradients, discharge of water to the slope, the resulting pore pressure distribution in fractured rock.

Chapter 7: Geotechnical Model

Data compilation and assessment, focussing on how the data presented in Chapters 3, 4, 5 and 6 is processed and made ready for use in the design analyses.  The aim of the chapter is to both highlight and provide guidance on those slope design issues for which clarification is frequently being sought.

Chapter 8: Data Uncertainty

Addressing the question of how to assess the reliability of information derived from data that represents only a small portion of a large parent group, and establishing a geotechnical reporting system that reports the uncertainties that are present in the geotechnical data to mine operators, corporate mine management, and the investment community.

Chapter 9: Acceptance Criteria

Outlining the current deterministic and probabilistic acceptance criteria used by management and the potential application of newly developed risk and consequence approaches to supplement the methods now being used.

Chapter 10: Slope Design Methods

Highlighting current and newly developed methods that may be used to predict, back-analyse, and formalise the slope design, optimise the bench, inter-ramp and overall slopes, and estimate the reliability of the final pit walls.

Chapter 11: Operational Considerations

Focussing on the operational requirements of mine planning, controlled blasting, slope protection measures, and artificial support.

Chapter 12: Slope Evaluation and Monitoring

Outlining measures to be adopted for evaluating the performance of the as constructed walls of the pit, slope monitoring and a ground management plan.

Chapter 13: Risk Management

Outlining how general risk management concepts and processes can be applied to the geotechnical risks associated with each stage of the open pit slope design process.

Chapter 14:Mine Closure

Covering the processes and issues to be addressed, statutory requirements, and NGO pitfalls in the mine closure process.
Public Release
A draft edition of the book has been typeset and was released to the sponsors for review and editing in November 2008.  Public domain English and Spanish language hard copies of the text will be released at the 2009 International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, 09-11 November 2009, at the University of Los Andes, Santiago, Chile

Rock Slope Stability 2009

Rock Slope Stability 2009 will provide a forum for open pit mining and civil engineering practitioners, consultants, researchers and suppliers worldwide to exchange views on best practice and state-of-the art of rock slope technologies.  Best practice with respect to pit slope investigation, design, implementation and performance monitoring shall be topics to be discussed during the Symposium.


The official language of the Symposium is English.  Simultaneous English-Spanish-English translation will be available.


Symposium registration and accommodation arrangements at a selected number of hotels in the Los Andes, Los Condes and Providencia districts of Santiago will be posted on the Symposium website (www.slopestability.cl) early in 2009.


The Organizing and Technical Committees of Rock Slope Stability 2009, with the advice of industry representatives, has selected the themes and topics listed below for structuring the technical program of the Symposium.  They reflect the main concerns and issues of the industry and follow the life of mine sequence from project development to closure that is followed in the Open Pit Slope Design Guidelines book that will be released by the LOP Research Project at the Symposium.

  • Fundamentals of slope design
  • Formulation of slope designs
  • Field data collection procedures
  • Geological and Structural models
  • Rock mass and Geotechnical models
  • Hydrogeology and ground water implications
  • Assessing and reporting data uncertainty
  • Slope failure mechanisms
  • Slope design criteria and design methods
  • Mine planning aspects of slope design
  • Performance assessment and slope monitoring techniques
  • Controlled blasting techniques
  • Blast damage mechanisms
  • Risk management for open pit mining
  • Open pit closure


The Organizing Committee of Slope Stability 2009 cordially invites all interested persons to present an abstract of their papers addressing one or other of the Symposium themes in accordance with following dates:

  • Submission of abstracts:  Before Tuesday, March 31st, 2009. Abstracts must be submitted to following email address: John.Read@csiro.au
  • Mailing to authors of acceptance or regret and mailing to authors of instructions for preparation of papers: by Friday, April 24th, 2009.
  • Receipt of camera - ready papers: by Friday, July 31st, 2009.

Abstracts must be prepared in a Word document and should be limited to less than 500 words.  The abstract is to provide a general scope of the work, a summary of the results, and the significance of the work and applications.  It should also include the title, author’s affiliations, and the contact author’s address, telephone and fax numbers, and email address.

All accepted written papers will be peer reviewed and published in the 2009 International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering Proceedings.


The following keynotes lectures have been scheduled as part of the Symposium Program:

Day 1:Premium Keynote on Fundamentals of Slope Design; Evert Hoek.

Day 2:
Data Uncertainty; John Read
Slope Design Methods; Loren Lorig

Day 3:
Performance Assessment; Mark Hawley
Risk Management; Peter Stacey


Chairman, John Read (CSIRO, Brisbane),
Peter Stacey (SMGL, Vancouver)
Zip Zavodni (Rio Tinto, Salt Lake City).
Bob Sharon (Barrick, Tucson)
Alan Guest (AGTC, Johannesburg) 
Warren Hitchcock (BHP Billiton, Tucson)
Ashley Creighton (Rio Tinto, Brisbane)
Loren Lorig (Itasca, Santiago/Minneapolis)
Peter Terbrugge (SRK, Johannesburg)
Ricardo Sepúlveda (AKL; Santiago)
Michel Galeb (División Andina, Codelco Chile)
Mark Hawley (Piteau, Vancouver)


Chairman:  Raúl Fuentes (Universidad de los Andes/SKM Minmetal Ltda., Santiago)
Jorge Crempien, (Universidad de los Andes, Santiago).
Ricardo Cortés, (Minería Chilena, Santiago)
Marco A. Alfaro, (Metálica Consultores, Santiago)
Fred Vanbrabant,


CSIRO Exploration & Mining, Queensland Centre for Advanced Technologies, Brisbane, Australia
Universidad de Santiago de Chile
Ministerio de Minería de Chile
SERNAGEOMIN – Servicio Nacional de Geología y Minería
COCHILCO - Comisión Chilena del Cobre
Consejo Minero de Chile A.G.
CONICYT – Comisión Nacional de Ciencia y Tecnología

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