The challenge for mining operations is to harness innovation to constantly improve the way in which mines are developed for long-term sustainability.

SKM has been working with Codelco in Chile on the New Mine Level Project (NMLP) for the world’s largest underground mine – El Teniente. The Pre-feasibility and Feasibility studies have been completed and the implementation phase is well underway. Project efforts have concentrated on maximising the use of new technologies for both construction and operations, along with the selection of the best mine infrastructure, to keep El Teniente operational for the next 50 years.

El Teniente copper mine is situated 80 kilometres South of Santiago and 2,500 metres above sea level in the core of a volcanic mountain, and has previously been developed on multiple levels, arranged around an intrusive volcanic, non-mineralised formation, called the Braden Pipe, where the mining infrastructure for each level is located.

The new development aims to access a rich copper deposit located under the current operational ore body. Reserves of 2000 Mt have been identified, which will be extracted from 2017, using the panel caving and progressive sinking method, with an end date of 2070.  There is a ramp-up period of 13 years to reach the maximum throughput of 180,000 t/d, which will be maintained for 18 years.

The NMLP will totally transform the way the mine has previously operated, which is in effect a “green fields” project, with respect to the implementation of fundamental changes in the labour and business environment.

The plan is to harness new technologies and operations to reduce mine operational risks and take advantage of new opportunities, such as remote, automated mining, to improve:

• Safety
• Working conditions and access for workers
• Risk management eg. from rock falls
• Productivity
• Energy efficiency eg. ventilation on demand
• Materials handling
• Maintenance

The NMLP is thought to be the largest underground mining project in the world with an estimated investment of over US$3 billion and described by Codelco as, “...environmentally, economically and socially sustainable - set in the future and utilising new technologies within the context of ore production.”

Existing Mine Infrastructure

The existing underground mine operation includes six mining sectors located in different elevations arranged around an intrusive volcanic, non-mineralised formation which houses the mining infrastructure. Access to the mine is through a 3.5 km tunnel and ore is hauled to the surface through a railroad system. On the surface it is dumped into crushing plants and from there conveyed to a concentrator where copper concentrate is produced. From there it is sent to a smelter.

An expansion of the mine in the 1960’s identified the Level 8 railroad as the main material handling system, constraining much subsequent development which had to consider the railroad as the main haulage system.

Opportunities for New Technologies and Innovative Design

The nature of the project in terms of depth, size and mining methods creates significant risks in terms of facilities and processes; the deepening of the mine and the increase of litho static pressure with a subsequent increase in rock mass stresses may create hazards that include collapses, rock falls, seismicity and rock bursts, water and mud floods, fire and machine injury.

Many of these risks are associated with the physical integrity and health of the workers. Remedies in the form of technological solutions have been assessed and will be introduced throughout the life span of the project. The location of the new level below the current mine facilities, and the long time frame for development creates opportunities to improve the quality of life for the workers and the sustainability of mining practices, both of which are at the forefront of the development.

Mine Design for Sustainability

1. Centralisation of Services
   Having a single, undercut level, as opposed to mining smaller sectors arranged on different levels, as currently occurs, allows for the centralisation of services and logistics in the Braden Pipe. The management, underground maintenance workshops, refuelling, workers’ change rooms, dining facilities and explosives storage will all be centralised. This will result in time savings, more effective maintenance, simplification of access, and a reduction in personnel.
2. Water Drainage
   Currently, the drainage of water from snow thawing and mine operations, is facilitated via various systems, raisers, shafts and pumps. The NMLP considers introducing an additional drainage level to collect water, separate solid particles and pipe it along the main conveyor belt to the surface, which will result in greater efficiencies.  
3. Improved Access
   A new access road to the mine will reduce travel time for personnel and materials from two hours to one hour in each direction, thereby improving effective working time and productivity. As the new road will be at a lower elevation, problems currently caused by snow fall will be diminished.
4. Non-Interference with Current Operations
   Locating the new mine level below the current transportation level and allowing access via a new road and ore handling via conveyor, means that there will be virtually no interference with current operations during the construction of the new mine, significantly enhancing productivity levels.

Technology for Sustainability

1. Materials Handling
   The new mine level will allow for moving the ore via a conveyor belt to a stockpile located on the surface, close to the concentrator.  The benefits of this system, as opposed to the current rail haulage, is its higher availability, reduction in operation cost and higher flexibility to reach the stockpile, opening up the potential for future expansion up to 240,000 t/d.
2. Automation and Remote Control
   The use of automation with remote control will significantly decrease the workforce exposure inside the mine and will allow for the monitoring of real-time rock mass behaviour. he remote operation will be controlled from a new corporate building 50 km from the mine site. 
   
   Benefits of employing this type of operation will result in:
   
   

   Improved personal safety by decreasing time spent in the mine Decreased illness by decreasing exposure to exhaust gases, dust, noise and vibrations Increased productivity with more effective working hours Lower maintenance requirements Lower fuel and energy costs  Greater effectiveness in driving equipment, processes (by using real-time and online information) and production schedules

3. Mine Ventilation
   Another novel concept will be the intelligent monitoring of ventilation through the mine. This is achieved through tags that will be carried by each of the operators and monitored by a system to quantify the amount of air required. This method allows a more efficient use of energy as well as safeguarding personnel.
4. Human Resources Management
   The use of robotics, automation and technological innovation will require skilled personnel proficient in these technologies; new skill profiles, recruitment and training models will be created to increase workforce optimisation and provide a safer, healthier outcome for the employees, which will be reflected in improved productivity.
5. Maintainability Management
   New management information systems, including online and real-time information, GPS and radio frequency identification, have been included to facilitate agile decision making, condition monitoring based maintenance and logistics plans that optimise the maintainability of equipment and facilities.
6. Energy Efficiency
   This concept will be widely used in the project, eg. in the case of mine ventilation, the application of a main fan control system using frequency convertors in the ventilation drives will deliver energy and operating costs savings.
7. Future Technologies
   Due to the long-term development period of the El Teniente NMLP, there is an opportunity for Codelco to be open and flexible to any future technological advancement that contributes to their goal of sustainable mining.

The El Teniente experience demonstrates the possibilities available to other mining organisations who might be considering extending their existing reserves, which will necessitate a deepening of mine infrastructure. Adopting Codelco’s vision to develop mining reserves with originality and accountability will be essential to ensure the sustainability of mining operations into the future.

© Sinclair Knight Merz
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