6 Sep, 2018, 12:25 - 12:40

Marcos Díaz Corvalán, Manager, ANDDES S.A.

Curriculum Vitae
Marcos is a Civil Engineer specialized in Construction Management and Execution. He graduated from the School of Engineering at the National University of Cuyo, in the province of Mendoza, Argentina, and holds postgraduate degrees in Project Management (based on the PMI guidelines), Financial Administration and Quality Management. He has 18 years of experience in mining projects, including positions such as Construction Manager, Superintendent, Field Service Manager, Project Director, Project Manager, Quality Resident Engineer, Quality Assurance Team Supervisor, and Earthwork Quality-Control Team Manager. He has also worked as the Head of the Water Works Program and as a Water Project Engineer for the province of San Luis government. Currently, he is the Construction Service Manager at Anddes Argentina S.A. Some of the main projects he has participated in are: Pucamarca, Lagunas Norte, Raura and Shahuindo, in Peru, and Lindero, FMC Minera del Altiplano, Pascua Lama, Veladero, Gualcamayo, Pirquitas, San José, Salar Antofalla, El Quevar, Cerro Negro and Cerro Moro, in Argentina. Marcos is also a Teacher at the National University of Cuyo. He has been a Head of Practical Assignments (JTP, by its acronym in Spanish) at the Chair of Civil Engineering Economy for over 15 years. Contents covered in that subject include bills of quantities and construction budgets, cost estimates and selection of equipment for earthworks, certifications and bidding processes. He also assists at the Chair of Project and Construction Organization, specifically in the areas of time management (according to the PMI) and use of the MS Project software.


The presentation will be based first on the design of the engineering of the Heap Leach Pad (HLP) Phase 1, the construction of a system with ponds and channels has been planned; they are located downstream of the HLP lowest point, and have been designed according to the final volume requirements, both for Phase 1 and Phase 2. The project considers the construction of a monitoring system to detect and convey possible cyanide solution leaks going through the liner, both at the leach pad and the ponds. The platform grading considers the construction of internal berms separating the solution collection, independently, in south-north oriented, 60-m-wide cells. The leach pad liner system will consist of a geosynthetic clay liner (GCL) or a soil-bentonite mix layer with a single-sided textured, 1.5 mm thick LLPE geomembrane installed on top of them. The textured side will be in contact with the GCL or the soil-bentonite mix layer. The soil-bentonite mix layer will be installed in the perimeter of the pad to ensure heap stability, while GCL will be placed in the rest of the area. The process ponds (barren, ILS and PLS), just as the pond for larger events and the SART pond, include a double liner system with a leak detection system made up of GCL to be installed on prepared soil, secondary geomembrane, geonet and primary geomembrane. A smooth HDPE 1.5 mm thick geomembrane will be used. Only the primary geomembrane will be conductive, which will make geoelectric leak detection testing possible before and during the operation. The purpose of such tests is the identification of possible geomembrane defects resulting from placement or damage occurred during operations, and the execution of required repairs. The design of solution collection pipelines in the pad considers the use of double-walled 100, 300 and 450-mm pipelines in the stacking cells. At the heap toe, the solution will be discharged through the main berm and will flow into solid, 450 mm diameter, SDR 21 pipelines, to be conveyed to the pond system. Design storage capacity for Phase 1 is 23.9 Mt. The crest of the first layer installed at Phase 1 is located 3690 m ALS, while the elevation of the last layer is 3740 m ASL (6 layers or 60 m). Similarly, the storage capacity of Phase 2 will be 64.8 Mt, thus reaching a total capacity of 88.7 Mt. The crest elevation of Phase 2 first layer is 3750 m ASL, while the elevation of the last layer is 3810 m ASL (13 layers). It is worth mentioning that, according to design criteria, the maximum stacking height of the complete leach pad area is 100 m. During construction, quality control tasks called CQC and CQA are performed. They include testing, inspections, observations and related functions during construction. Their purpose is that tasks are conducted according to the quality standards required in the drawings and technical specifications. Additionally, as part of the CQA tasks, Geoelectric Leak Detection (GLD) techniques are used. Such techniques are based on the fact that the geomembrane is an insulating material and when it is not broken, electricity cannot pass through it. The direct GLD methods applied to the geomembrane and the indirect methods applied to the materials covering the geomembrane will be described. This last method is mainly applicable to leach pad projects or salt flat evaporation ponds.