This essays deals with the opportunity and danger of the El Teniente Copper Mine. At the beginning it focues on the geology of the desposits and the genesis of the El Teniente ore bodies. Afterwards it continues with the history of the mine and the infrastructure. The next point is panel caving and its process and modeling. Accordingly it goes on with the advantages and disadvantages of panel caving and the rock mass damage of the Esmeralda level. The term paper ends with a conclusion.
It contains large amounts of chalcopyrite of various grades. As the upper ore bodies have been extracted in the past, mining focuses on large, deep, and low-grade ore bodies. The only mining method capable of extracting these rock masses with high production rates and low production costs is block caving and its variation panel caving. Therefore Codelco started the largest mining operation in the world. The New Mine Level Project covers the entire footprint of the ore deposit, divided in 5 panels (Sur, Andes Sur, Andes Norte, Norte, and Pacifico) and will start to produce in 2017. The mine is located in midle to late Miocene extrusive and intrusive igneous rocks, which are part of the Farellones Formation.
Table of Contents
1. Geology of the Deposits
2. Genesis of the El Teniente Ore Bodies
3. The Mine´s History
4. Existing Mining Infrastructure
5. El Teniente goes deep
6. Panel caving
6.1 Process of panel caving
7. Block caving modeling
8. Advantages and disadvantages of panel caving
9. Rock Mass Damage of Esmeralda Level
10. Conclusion
Objectives and Topics
The primary objective of this work is to provide a comprehensive analysis of the El Teniente New Mine Level project, focusing on the technical challenges associated with deep-level underground mining. The research aims to evaluate the geological context, the implementation of panel caving as a primary extraction method, and the geomechanical risks, particularly those related to rock mass stability and stress distribution in deep, large-scale mining operations.
- Geological characteristics and genesis of the El Teniente copper deposit.
- Technical infrastructure and operational advancements in the New Mine Level project.
- Mechanics and modeling of panel caving and block caving mining methods.
- Risk assessment regarding rock mass damage, seismicity, and abutment stress.
- Lessons learned from historical collapse events at the Esmeralda level.
Excerpt from the Book
Rock Mass Damage of Esmeralda Level
Between 2001 and 2010 two major collapse events happened at the Esmeralda Mine level, causing massive rock mass damage in both undercut and extraction level pillars. The rock mass damage process depends on its characteristics and properties, the stress path and distribution and other boundary conditions. The overall collapse process took place within few weeks to some months. The damage process in drifts started at its periphery, where the confinement stress was lower and micro-cracks formation started. Crack density within the rock increased until a critical density was reached and macroscopic fracture coalescence occurred. This condition led to rock spalling where fractures are orientated mainly parallel to the principal minor stress. During the failure process, the stress trajectory moved towards the interior of the rock mass until a new stable condition was reached.
This stable condition is typically a “V-shape” over-break shape. A drift of this shape has a larger excavation free span and thus is less stable. Another feature that occurred in drifts of that level is volumetric dilution of rocks, which together with geometric incompatibilities of the broken rock, cause rock mass bulking. This is especially hazardous where haulage and drawpoint drifts intersect. In those areas, the larger excavation free span and corners decrease the degree of confinement of the rock mass. The volumetric dilation of rock and rock mass bulking led to complete collapse of excavation sections in the Esmeralda block (Gomes et al., 2016).
Summary of Chapters
Geology of the Deposits: This chapter details the porphyry-style copper deposits found in the Chilean subsurface, specifically highlighting the formation and mineral composition of the El Teniente site.
Genesis of the El Teniente Ore Bodies: It explains the multi-stage formation of the ore deposit over millions of years, driven by magmatic-hydrothermal processes and mantle-derived magmas.
The Mine´s History: An overview of the mine's development from the 16th century to its nationalization by Codelco in 1971.
Existing Mining Infrastructure: Describes the extensive tunnel network and the current mining blocks utilized for extraction around the Braden Pipe.
El Teniente goes deep: Focuses on the New Mine Level project, outlining the technological shift toward automation and the challenges of mining at significantly greater depths.
Panel caving: Defines panel caving as an efficient large-scale method for extracting low-grade ore and describes the infrastructure requirements for the extraction process.
Block caving modeling: Discusses the geotechnical parameters required for successful caving, including stress performance and rock mass classification.
Advantages and disadvantages of panel caving: Evaluates the cost-efficiency of caving methods versus the risks associated with rock mass behavior and abutment stresses.
Rock Mass Damage of Esmeralda Level: Analyzes the causes and consequences of major collapse events, providing critical insights into pillar failure and rock stability.
Conclusion: Summarizes the challenges of deep-level mining and stresses the necessity of real-time monitoring and learning from past geotechnical failures.
Key Words
El Teniente, Copper Mining, Panel Caving, Block Caving, Rock Mass Damage, Esmeralda Level, Geomechanics, Abutment Stress, Mine Infrastructure, Codelco, Porphyry Deposit, Seismic Events, Ore Extraction, Subsurface Mining, Rock Quality Designation.
Frequently Asked Questions
What is the primary focus of this publication?
The publication examines the technical and geomechanical challenges of the El Teniente New Mine Level project, with a specific focus on panel caving in deep-level mining environments.
What are the core themes addressed?
Key themes include geological formation, infrastructure development, mining methodology, and the mitigation of rock mass instability in large-scale operations.
What is the main objective of the New Mine Level project?
The project aims to access over 2 billion tonnes of low-grade ore, effectively extending the production life of the mine by 50 years while maximizing efficiency through automation.
Which mining method is primarily discussed?
The work centers on panel caving, a variation of block caving, as the primary method for extracting rock masses with high production rates at low costs.
What topics are covered in the main section?
The main sections cover geological history, infrastructure design, the mechanical modeling of caving, and an in-depth analysis of rock mass damage experienced at the Esmeralda level.
How would you describe the document's key terminology?
The document relies on specific mining and geological terminology such as "caving," "abutment stress," "drawpoints," "RQD," and "hypogene mineralization."
What caused the significant damage in the Esmeralda level?
The damage was attributed to a combination of factors, including the used caving method, insufficient blasting, unfavorable extraction angles, and exposure to high abutment stresses over extended periods.
How is the New Mine Level project addressing the risks of deep mining?
The project utilizes technological solutions like semi-automated LHDs, real-time monitoring, and optimized operation sequences, specifically incorporating lessons learned from the Esmeralda collapses.
Why is the "caving radius" important in this study?
The caving radius is a critical parameter for estimating rock mass behavior; however, the study notes that standard empirical methods become less reliable at depths exceeding 500 meters.
- Citation du texte
- Adam Valenzano (Auteur), 2017, The opportunity and danger of panel caving in the El Teniente copper mine, Munich, GRIN Verlag, https://www.grin.com/document/371924
