Columbus Gold Corp. is pleased to provide an update on the advancement of the ongoing Bankable Feasibility Study and Environmental and Social Impact Assessment at its 100% owned Montagne d'Or gold deposit, French Guiana.
The studies are being funded by Nord Gold N.V. (LSE: NORD LI) pursuant to which they can earn a 50.01% interest (for a total of 55.01%) in Montagne d'Or.
In October 2015, Lycopodium Minerals Pty Ltd. was awarded the contract to complete a BFS on the Montagne d'Or gold deposit, in conjunction with SRK Consulting (U.S.) Inc. The BFS is anticipated to be completed in the fourth quarter of 2016 and entails the development of an engineered construction and operating plan with considerations for social, environmental and water management, permitting, geotechnical engineering, hydrogeology, metallurgical testing, process design and mine planning. The project is to be developed on the basis of open pit mining.
In June 2014, WSP Canada Inc. won the tender to complete an ESIA in order to obtain the various authorizations required for mine construction and eventual mining operations. Complementary studies that will accompany the ESIA include a Hazard Study / Risk Assessment (EDD), Internal Operation Plan (POI), and Security and Health document (DSS).
Geology and Mineral Resource
An infill drilling program was completed between November 2015 and March 2016 consisting of sixty-two (62) core and RC drill holes, for a total of 6,580 meters. The program was designed to upgrade a portion of the Indicated resources to the Measured category with a 50-meter by 25-meter drill array over a strike extent of 550 meters and to a maximum vertical depth of 125 meters, within the anticipated starter pit (west section) of the deposit. Twenty-seven (27) holes were completed in the principal UFZ zone and thirty-five (35) holes in the secondary LFZ zone. Results of the drilling were disseminated in News Releases dated December 10, 2015 and April 22, 2016. The program was successful in confirming the good continuity of the gold mineralized zones and the higher grades within the west section of the deposit.
The drillhole database and 3-D geological and structural models were provided to SRK for validation and to carry out an updated resource estimation.
Extensive metallurgical studies were conducted on the UFZ and LFZ master composites and seven variability composites as part of the Preliminary Economic Assessment ("PEA") announced on July 8, 2015. The 2015 program evaluated a variety of process options including: whole-ore cyanidation, gravity concentration followed by cyanidation of the gravity tailing and gravity concentration followed by gold flotation from the gravity tailing and cyanidation of the flotation concentrate. Based on those studies the process option that includes gravity concentration followed by cyanidation of the gravity tailing was selected for advancement of the BFS.
The 2016 metallurgical testing is being conducted on three master composites (UFZ, LFZ and saprolite/saprock), twenty-two variability composites, and six comminution variability composites.
In addition, the 2016 program includes:
- Extended gravity recoverable gold (E-GRG) tests on each of the three master composites;
- Static and dynamic thickening studies on the cyanidation leach residues; and
- Carbon adsorption and modeling studies on each of the three master composites.
The metallurgical testing on the composite and variability samples is almost complete with results to date confirming those used for the PEA. The fresh rock mill feed, while of average to high competency, demonstrates low grinding energy requirements. Gold recovery by gravity concentration and cyanidation is high, ranging from 92 to 97% at a grind size of P80 75 microns with no indication of preg robbing or other adverse metallurgical characteristics. Furthermore, intensive cyanidation is reported to leach 98-99% of the gold contained in the gravity concentrate.
Geotechnical Engineering & Hydrogeology
The geotechnical / hydrogeological drilling and logging program amounted to 46 HQ3 core holes, for a total of 4,687 meters, and 34 test pits for geotechnical characterization of soils (saprolite) and hard rock within the projected pit, mine infrastructure, and tailings, waste and stockpile storage sites. The 3-D structural model was supported by the geotechnical drill program.
Phase-1 rock strength testing was completed and results for Phase-2 are anticipated in late May. Data analysis and reduction of field data to support rock mass characterization for pit slope stability analysis and determination of recommended slope angles for the surface saprolite layer and hard rock is in progress.
Eleven (11) holes of the program were directed at hydrogeological characterization within and outside the projected pit. The program included packer testing for physical characterization of the rock, identification of geologic units and structures, and piezometer installation for continuous measurements of groundwater flow directions, gradient monitoring and sampling.
Hydrology and Water Management
The Water Balance model has been completed to a preliminary level. A model of preliminary estimates of water demands and surpluses and estimation of storage requirements is in progress.
A core sampling program of waste rock and low grade ore was carried-out for detailed geochemical testing including acid-based accounting ("ABA"), multi-element analysis, leach tests and mineralogical analyses. Static and assay testing is nearing completion and kinetic testing is in progress.
Metallurgical test samples are also subject to similar tests for geochemical characterization of the mill tailings. Tailings static and assay testing are complete for detoxification and kinetic testing is in progress.
A first batch of 11 groundwater samples from the hydrogeological drill holes and one surface water sample was sent to a laboratory for testing, and partial data has been received.
Tractebel Engineering is in the final stages of completing a detailed study on connecting the Montagne d'Or project to the national power grid (see News Release dated December 30, 2015). Aerial and buried options for a 90 KV line are being examined in consideration of a 20 MW requirement for the mine. The base case assumption in the 2015 PEA was that energy could be generated on-site at a cost of approximately US$0.20/kWh. It is anticipated that a grid connection could reduce energy costs by up to 38% or to US$0.12/kWh, resulting in significant savings over the life of the mine, noting that energy is one of the largest components of operating costs.
Infrastructure and Mine Design
The scope of the required access roads and site supporting infrastructure has been defined and preliminary studies and design work are underway. A preliminary design of a 4.5 Mtpa process plant is well advanced with flowsheets completed, preliminary layouts done, equipment lists well advanced and equipment selection and pricing in progress. Design work on the tailings storage facility is underway. A preliminary site water balance study is close to completion.
Labor Costs and Tax Regime
Preliminary cost estimates were produced incorporating specific French and French Guiana labor laws and regulations in terms of salaries, work hours, shifts, source deductions, and social security. A detailed analysis of regional and national tax schemes, including the possible availability of tax credits, subsidies and other tax incentives, is in progress.
ENVIRONMENTAL AND SOCIAL IMPACT ASSESSMENT (ESIA)
Baseline Studies and Environmental Scoping Study
The field work programs for the baseline environmental studies were completed in early November 2014. The objective of these studies was to collect background information to establish pre-project conditions of the physical environment (geology, geomorphology, soils and sediments, hydrology and hydrogeology, landscape, climate), the biological environment (ecology, natural habitats, fauna and flora, protected species) and the social and economic setting (air quality, noise and vibration, socio-economics, natural resource use, cultural heritage and archaeology).
An Environmental Scoping Study report produced by WSP was submitted to the government environmental authority ("DEAL") in August 2015. A two-day scoping session was held with the DEAL, the National Forest Office ("ONF") and the Department of Cultural Affairs ("DAC") in October 2015 to present the results of the baseline studies and identify gaps for the completion of the final ESIA.
In response to recommendations of the DEAL, ONF and DAC, three (3) complementary biological surveys were completed in and around the projected mine site area and preventive archaeology surveys will be carried out in the coming weeks. Additional biological surveys are also planned along the access road.
Environmental Impact Assessment
Based on the technical description of the project and the results of the baseline studies, WSP and its local consultants are currently identifying the potential impacts on each of the components included in the baseline studies. Appropriate management measures (Avoidance, Reduction, and Compensation) will be proposed in order to minimize the impact of the project.
The completion of the ESIA is anticipated for the fourth the quarter of 2016 to support the BFS. The final report will be submitted to the French Ministry of Ecology, Sustainable Development and Energy in the first quarter of 2017.
Hazard Study / Risk Assessment
Hazard and Risk Assessment studies are being carried out with complementary studies that include: Explosive Atmosphere Areas Study (ATEX), Pyrotechnic Safety Study, Safety Notice, Risk Analysis for the Tailings Facilities and Lightning Risk Analysis. An Internal Operational Plan (POI) and a Transport and Storage of Hazardous Materials Study will also be completed. A kick-off meeting for the EDD was held in February 2016 with the participation of the DEAL and their third party experts.
Closure and Rehabilitation Plan and Environmental and Social Management Plans
To comply with the national and local requirements, mine closure and rehabilitation plans will also be developed. These will include, among others, the Water Management Plan, Erosion Control and Re-Vegetation Management Plan, Biodiversity Management Plan, Pollution Prevention Management Plan and Waste Management Plan.
Three rounds of information and consultation sessions with stakeholders were scheduled during the development of the ESIA. A first round of consultations was carried out by WSP in French Guiana in September 2014. The second round is currently in progress (May 2016) involving a larger segment of stakeholders. The third round is planned for late 2016. The meetings are intended to provide information on the development of the project and allow stakeholders to express their concerns and expectations, convey recommendations, and participate in the identification of issues for the implementation of appropriate management measures.
Several rounds of consultation in French Guiana were undertaken by Dr. Michel Jébrak in 2015 and 2016 in order to develop job training programs to fill the various technical and laborer positions required for mining operations. Dr. Jébrak is Professor at the Department of Earth Sciences at the University of Quebec in Montreal (UQÀM) and École des Mines de Nancy, France, and a consultant in sustainable mine development to Columbus Gold. Following the consultation rounds, a mining geology program is being implemented at the University of French Guiana in Cayenne and job training programs with the RSMA army regiment, based in Western French Guiana. The RSMA has set up similar programs for the mining industry in New Caledonia. Columbus Gold is aiming to source locally up to 90% of the workforce for the Montagne d'Or Mine.
Montagne d'Or Gold Deposit
The Montagne d'Or deposit consists of closely-spaced sub-parallel east-west-striking and steeply south-dipping gold-sulfide mineralized horizons. The deposit is presently drill-defined over a strike extent of 2,300 meters and to an average depth of 250 meters from surface. The mineralized zones remain open on strike to the west and at depth. Utilizing a cut-off grade of 0.4 g/t gold, the deposit* hosts Indicated mineral resources of 83.2 million tonnes grading 1.45 g/t gold (3.9 million ounces) and Inferred mineral resource of 22.4 million tonnes grading 1.55 g/t gold (1.1 million ounces) (refer to News Release dated April 21, 2015).
A Preliminary Economic Assessment ("PEA")** for the Montagne d'Or deposit was completed by SRK Consulting (U.S.) Inc. in July 2015 (refer to News Releases dated July 8, 2015 and August 4, 2015). The PEA estimates approximately 273,000 ounces of gold produced per year in the first 10 years of production at an All-In Sustaining Capital Cost per ounce of US$711, and a mined head-grade of 2.0 g/t gold.
Bret Swanson of SRK Consulting (U.S.), Inc. of Denver, CO., an "Independent Qualified Person" as defined by National Instrument 43-101, has reviewed and approved the content in this news release.