NEXT TRAINING MODULES TO COME

CESECO 2: 28/09/15 – 23/10/15

28/09/15 – 02/10/15, soil and rock mechanics (CESECO 2A).

05/10/15 – 09/10/15, slope stability and mass movement in open pit mines (CESECO 2B).

12/10/15 – 16/10/15, introduction to underground water and water management in mines (CESECO 2C).

19/10/15 – 23/10/15, rock fragmen-tation techniques (CESECO 2D).

CSFG 2: 21/09/15 – 16/10/15

21/09/15 – 02/10/15, linear geostatistics: modeling (CFSG 2A).

05/10/15 – 16/10/15, linear geostatistics: estimation (CFSG 2B).

CSFG 3: 26/10/15 – 30/10/15

26/10/15 – 30/10/15, non stationary geostatistics.

Romain Soubeyran Director of Mines

ParisTech

Goodbye to our 2014-2015 students! On July 9th 2015, it was a great pleasure for us to present the diplomas to the students of the three Specialized Training programs: CFSG (Geostatistics applied to the mining industry), CESECO (Technical and economic analysis of mining open pit) and CESAM (Public administration of mines). R. Soubeyran, Director of MINES ParisTech, said that if "we offer at MINES ParisTech, various courses in a wide range of technical domains, our commitment to the training programs for the mining industry is special because it is all about our roots. “Mines” is where we come from… For more than 35 years with the creation of CESMAT, we have believed that vocational training is mandatory to cope with technical evolutions and meet environmental and social challenges for the mining industry in the future. Despite the end of public financial support several years ago, we decided to maintain these training programs." All together with the training managers, J.A. Fleurisson (CESECO), G. Loc'h (CFSG) and H. Accarie (CESAM), "we would like to warmly thank the companies and institutions that have continuously trusted us. It is for us the best evidence that we fulfill a real need to help engineers to address technical, environmental and social challenges of this industry…And the success of the students is the best encouragement to our professors." This year, 15 students from 10 countries on 4 continents (Brazil, DR of Congo, France, Ivory Coast, Madagascar, Mongolia, Niger, Peru, Rwanda and United Kingdom) were graduated. The training managers underlined "the work done by all the students with energy and good mood… Beyond the professional exchanges we had with you, we also greatly appreciated the more cultural and friendly exchanges. We hope you have enjoyed your stay in France and we are going to maintain a long term relationship with you. One of the advantages of these training programs is to gather engineers from a large variety of countries and build an international community of people who know and trust each other ... We also want to thank the French mining companies and consultants who bring their expertise and share their professional daily experience." Congratulations to all the students and good luck for their future career!

September 2015 – newsletter n°2

To subscribe to the newsletter send an e-mail to: Patricia.fraile@mines-paristech.fr Geosciences & Geoengineering Research Department - professional continuing education in mining industry

Exceptionally in 2015, courses will be delivered in French (except if English speaking students are present)

Ousseini ABDOU (CESECO) Geological modeling and resource estimation of Abelajouad uranium deposit (Niger). The Tim Mersoï Basin (Niger) contains important sandstone hosted uranium deposits and more especially 15 uranium exploration targets have been identified within the Abelajouad permit. They are based on geological criteria, drill-hole data and feasibility studies data. Starting from the available drilling data, this work is aimed at building a geological model and a block model using Surpac software in order to evaluate the resource in Uranium in the Adelajouad deposit. The uranium grades were estimated using three methods: inverse distance, geometric grouping and ordinary kriging from the measured grades of logging. The three methods gave very similar results in terms of tonnages but there is a small discrepancy in grade values.

Amel BECHIRI (CESECO) Economic evaluation for “Nimba” iron ore project in Guinea republic The valuation of a mineral asset depends on the targeted purpose, the development stage of the project, the technical aspects for decision-making procedures, the capital investments and the uncertainties related to the specific characteristics of the deposits. The objective of this work is to study the economical evaluation of “Nimba detrital iron ore project”, to analyse its viability and sensitivity to different parameters with time. The Discounted Cash Flow is the

suitable methodology chosen for this project of open pit mines for a lifetime over 20 years. Sensitivity analysis shows that the project is very sensitive to change in iron ore price.

Mamane KACHE (CESECO) Improvement of drilling and blasting techniques at SONICHAR coal open pit mine (Niger) This project work discusses the improvement of drilling and blasting operations at SONICHAR coal open pit mine in Niger Republic. Ash and William formulas were used to evaluate the blasting data and led to an acceptable pattern of 5.25m x 8m. The values of the other drilling parameters were determined. It was also found that the removing of the superficial soft part of the first bench by a bulldozer could lead to decrease the quantity of explosives and the number of meters to be drilled. The real specific energies are not enough to efficiently break the rock (sandstone). Also, the decrease in drillhole diameter to 120 - 125mm could lead to optimize the production blasts.

Arsene YAO KOFFI (CESECO) Monitoring and optimization of optical sorting talc performance The optical sorting plant of Imerys Talc in Luzenac allows recovering the part of the whitest talc from the standard grey ore. The optical sorting allows the suitability of the mining level of the deposit (5% of white talc) and the market needs (10% of white talc). It processes about 180 000 tonnes of talc per year for about 40 000 tonnes of white products. A new optical sorter was bought by the company in order to be able to sort the fine particlse with a diameter lower than 5 mm that was not possible with the old equipment. The performed work was focused on the analysis of the sorting performances in order to identify the limits in particle size and maximal output with the objective to improve the performances in terms of mass yield and recovery of white products. Francis KAYUMBA (CESECO) Geological modelling and resource evaluation of a copper deposit based on results of a computer-assisted exploration programme by using Surpac software The presented work is an application exercise of geological modeling and resource estimation of a fictitious copper deposit. Based on geological map and first drilling results, additional exploration and drilling works toward north and eastern part of the previous drilled and anomaly area have been defined. The CLAIM computer based exploration model was used to get the drilling results in terms of geology, mineralogy and grade distribution. All the data were then used in SURPAC software to create the geological block model and calculate the ore tonnage and average grade.

Geosciences & Geoengineering Research Department - professional continuing education in mining industry

Eder LAGOS (CESECO) Real Options in Brownfield Mining Projects “Salt star” layback, a gold mining project located in the USA, is an extension of a current mining operation. The stripping ratio of this project is high and ore with the highest grade is located at the bottom of open pit. It is therefore a risky or marginal project, but it doesn’t require high investment. The mining project was analyzed by the real options method in order to compare different financial assessments and different ways considering changes in costs, prices, cut-off values, mining plan and use of stockpiles. The Monte Carlo method was used to analyze the financial risk (% of simulations resulting in a negative NPV). The use of variable differential cut-off grade by year and stockpiles by grades reduces the probability of generating a negative NPV. For the "Salt stars" mining project the financial risk is therefore reduced from 34% to only 2%.

Emma SHEARD (CFSG) Geostatistical Analysis and Simulation of the Sheini Hills Iron Ore Deposit, Ghana, Africa The Sheini deposit is a large tonnage but low to medium grade iron ore deposit located in the Republic of Ghana. The current project presents the stochastic modelling of the geometry of this deposit, combining several geostatistical methods: unfolding, stochastic geological modelling using Truncated Gaussian simulations and 3D potential-field method. Then conditional simulations of the grades are run for the univariate (Fe only) and multivariate cases (Fe, SiO2, Al2O3, P and S), the simulations being conditioned by facies simulations. Grade simulations were carried out in the flattened grid system, with final results and recoverable resources analysed back in real space. The results are analysed through grade-tonnage curves. It confirms the utility to consider the separate facies and to take into account the deleterious material when evaluating iron grades by simulation.

Daniel-Bailon BATALE BANGONGO (CFSG) Geostatistical Study of Megi Gold Deposit (Rangold / RD Congo) Megi Gold Deposit, in Democratic Republic of Congo, is still in exploration (pre-feasibility) phase. This geostatistical study is focused on the estimation of in situ and recoverable resources. Estimation of in situ resources is done using two methods, Ordinary Kriging with capped value and Top-cut method (Rivoirard 2013), to take extreme values into account in a better way. These two methods are applied first on raw grades (as usual in the company) then on accumulation (grade x density) to ensure that geostatistics is used on additive variables. For

the estimations of recoverable resources two approaches have been used: Uniform Conditioning to go from Panel estimation to an evaluation of the probable Selective Mining Unit and Direct Block Simulation method to forecasts directly the recoverable resources of the Selective Mining Units. Tiago WEBBER (VALE) (CFSG) Joint Geostatistical Analysis of Drillhole and Geophysical Information for Lithotypes Boundaries Assessment The building of a 3D geological block model is usually the starting point for resource estimation and classification, followed by mine planning. The available data often do not allow reducing the uncertainties on geological contacts and boundaries. The aim of this project is to use density contrast obtained from geophysical airborne survey to reduce this uncertainty in a Brazilian Iron ore deposit. It focuses on the definition of the contact between lithotypes and tries to determine a geostatistical methodology to combine information from geophysics, prospecting and geological interpretation. Two methods are tested, both with and without the use of geophysical measure as collocated variable: indicator kriging and conditional probability estimation. The quality of the result is better for contacts between lithotypes presenting a high density contrast. Conditional probability estimation usually leads to better results.

Geosciences & Geoengineering Research Department - professional continuing education in mining industry

Heriniaina RANDRIAMAHALEO (CFSG) Estimation des teneurs en Al2O3, Fe2O3 et Alcalins pour le calcul des ressources dans la carrière d’Andalousite de Glomel Andalusite is a refractory industrial mineral (Alumina silicate) which is quite uncommon worldwide. The ore quality depends on alumina grade, but decreases when the grades of iron and magnesium oxides increase. This project compares different methods of grade modeling and evaluation for Glomel andalusite quarry. Several choices are tested for the geostatistical structural analysis as well as for the kriging estimation: univariate or multivariate study, with or without the waste data coming from the dolerite veins… The methods are tested and compared using several drillholes grids, to evaluate the possibility of using a coarser grid for the pre-exploitation drillholes.

Sylvain PETITEAU (AREVA) (CFSG) Revue de la procédure de simulations plurigaussiennes utilisée sur les gisements uranifères de type roll-front, et mise à jour d’une étude existante Stochastic modeling performed at Areva makes the first stage of prediction of Uranium production in roll-front orebodies by in-situ recovery (ISR). This project presents a methodology of updating a former model built on exploration drillholes, when new information coming from production wells is available. Data homogenization allows first to regroup both sets of data, and to check the consistency between the initial simulations and the new production data. It is then possible to decide if an update is necessary. The different steps of Plurigaussian simulation

method are then checked with a critic and evaluation of the usual methodological choices with in some cases proposal of new choices. Arman MELKUMYAN (CFSG) Geometric Modeling of the El Teniente pipe: A New Alternative Modeling the geometric boundaries of mineralization is of significant importance to define the limits of the deposit and constraint the evaluation of recoverable resources. This project is devoted to the modeling of the El Teniente Pipe geometry. El Teniente is a complex multistage copper Cu-Mo orebody with a poorly mineralized pipe surrounded by the ore geological unite. The surface of the pipe defines the internal limits of the orebody. The geometry of this pipe has earlier been modeled by Séguret and Celhay (2013). This study develops three alternative approaches of increasing complexity. These new approaches use the geometric quasi symmetry of the pipe, solve the problem in a cylindrical coordinates system (taking into account the periodic nature of the angular coordinate) and identify (and use) the drift present in the dataset. Béatrice FORÊT (CFSG) Estimation of the in situ and Recoverable Resources of a Gold Deposit This geostatistical analysis of a massive sulfide gold deposit aimed at analyzing the spatial variability of the gold grade, in order to estimate the in-situ resources in a long term block model and predicting the recoverable resources in the selective mining unit (SMU). After identification and delimitation of two estimation domains, three models are tested, with the corresponding kriging estimation methods, to estimate in-situ resources: the Truncated Grade model (=”capped” model), the Top Cut model and a reconstructed global model obtained from Top Cut model. The methods give very similar results. Then recoverable resources are computed using Uniform Conditioning based on panel estimation obtained by kriging with the truncated grade model. At mining cut-off, comparison with grade control block model shows a good match for ore tonnage but not so good for metal tonnage.

Geosciences & Geoengineering Research Department - professional continuing education in mining industry

Alan ROJAS KARI (CFSG) Stochastic Geological Modeling and Multivariate Recoverable Resources Evaluation in a Lateritic Nickel Deposit In a lateritic Nickel deposit, two features are of major concern.

Weathering concentrates the Nickel in saprolite, the rocktype closer to unalterated bed rock. The first part of the study models and simulate this contact, as well as the geometry of internal heterogeneities (waste saprolite / ore saprolite) using Plurigaussian simulations.

In addition to nickel, other elements which mark the weathering process and can impair the plant process (Fe2O3, Al2O3, MgO and SiO2) are important to evaluate the ore quality. The recoverable resources evaluation must take into account these elements in addition to Nickel. The resource evaluation is handled using multivariate Direct Block Simulations.

The comparison of results for a Neo Caledonian nickel deposit shows that both methods are consistent, but it is more advisable to use Direct Block Simulations method which provides a more complete evaluation.

Assanou MOUTARI (CESAM) Contribution pour l’amélioration du contrôle et suivi des activités des sociétés de recherches minières au Niger (in french)

Niger, with a sedimentary basin rich in uranium deposits and a region of interest by the presence of greenstone belts, has become an attractive place since some decades. Beyond financial interests (14.72% of the current revenues of the state, 85% of export earnings and 6% of GDP), Niger must also ensure the protection of its people, the preservation of its environment and its basement. The objective of this work is to make a diagnosis of control system and monitoring of mining activities. He highlighted that despite efforts, it is and remains insufficient, because most texts that meet the requirements of the moment, the lack of financial resources and the lack of adequate technical and logistics and insufficient

and inexperienced staff. On a purely technical level, procedures have been developed to carry out the control and monitoring instituted by the mining code.

Dulmaa DASHZEVEG (CESAM) La Mongolie, nouvel eldorado minier ? Ex member countries of the Soviet Union, little publicized internationally, Mongolia however not without assets. Countries rich in minerals, Mongolia, among the 10 countries with the fastest growth, encouraged foreign investment so that the market is now dominated by several global companies. These numerous foreign investments have hoped to achieve, over the long-term average, a level of development similar to Western standards. The contract for the Oyu Tolgoi (copper largest untapped reserves in the world) in Rio Tinto controls is one of the world's largest mining projects. This study is not exhaustive, allowed us to analyze the structures type of foreign direct investment, particularly critical for the Mongolian economy, but also the recommended legal cover in an emerging country. A dynamic analysis of the global market and its direct actors led ultimately to understand whether other companies were able to invest as heavily as Rio Tinto. Centre de Géosciences - Formation professionnelle spécialisée en ingénierie minière