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Santa Cruz, Province of Argentina Gold Mine

M3 is providing Engineering, Procurement, and Construction Management (EPCM) services for a gold mining project located in the Santa Cruz Province of Argentina. Once in full operation this mine will process 4,000 DMTPD (dry metric tons per day) of ore through crushing, single stage SAG mill, with agitated leach, counter current decantation, and gold and silver recovery in a Merrill-Crowe process plant.

Construction continues year round while M3 completes the final design and construction documents from the Tucson, Chandler and Hermosillo offices. Procurement and Construction Management efforts are managed from M3’s office in Buenos Aires and the project site.

The project team operating in an international work environment with a multi-language team is a continuance of M3’s successful history providing EPCM services for very challenging projects. This mine, once in full production, will be one of the largest gold processing plants in the region.


M3 is responsible for the Engineering, Procurement and Construction Management (EPCM) for the Peñasquito Project, located in the state of Zacatecas, Mexico.

The sulphide material processing facility consists of two equal circuits of a conventional SAG mill, two ball mills, a pebble crusher, HPGR, and a sulphide flotation plant producing lead and zinc concentrates with some gold and silver content.  The oxide and mixed ore grade material are placed run-of-mine on a lined heap leach facility for recovery of the gold and silver.

While the project is under construction, M3 continues the design at all of M3 offices in Tucson, Chandler, Hermosillo and Concepcion del Oro, Mexico. Oxide ore processing plant was completed and started production in May 2008 while the leach pad construction continues on its multiple phases.  Placing early purchase orders for major process equipment with long lead delivery time has expedited the engineering and construction schedule to allow an early construction start.

Peñasquito is the first mining project connected  to Mexico’s main power grid at a voltage level of 400kV, which includes a 400kV switchyard substation, 43kM of 400kV transmission line and a 200MVA step down substation 400-69kV.

Once completed, the Peñasquito project will be the largest mining processing plant in Mexico with a total design production capacity of 130,000 tonne of ore per day production thru the concentrator plant and at construction cost of 1.5 billion dollars.


M3 is responsible for the Engineering, Procurement and Construction Management (EPCM) for the Escobal Project in Guatemala, 70 kilometers east-southeast of Guatemala City and two kilometers east of the picturesque town of San Rafael Las Flores.  The ore, mined by underground methods, is processed at 4,500 metric tons per day using conventional crushing-grinding and froth flotation.

Several unique site challenges include high seismic activity and high seasonal rainfall. The site is covered with a 12 meter thick, low density pumice ash layer. M3 designed and constructed an 11 cubic meter per second fabric formed concrete channel to divert gradient storm water, prior to commencing major earth movement and concrete works.

The Dry Stack Tailings Facility is projected to be 100 meters high and includes a foundation key with ground water controls to promote stability. As each tailing outslope lift is completed, the slope is concurrently reclaimed by placing salvaged topsoil and seeding with a native seed mix, such as coffee, to blend in with the agricultural surroundings and provide a tangible long term benefit to the local community.

Located in a very compact footprint and in a narrow valley, M3 designed Escobal to maximize work flow and efficiency while minimizing the disturbance to the surrounding terrain, further reducing reclamation and closure costs. M3 continues to provide innovative and cost effective solutions to these challenges.

Buenavista del Cobre Concentradora No. 2

The Buenavista del Cobre Concentradora No. 2 project is a copper-molybdenum deposit in the northern-central part of the State of Sonora, Mexico, about 155 miles (250 kilometers) northeast of Hermosillo, and 27 miles (45 kilometers) south of the US border. The deposit is mined by open pit methods.

M3 provided engineering, purchasing and construction management (EPCM) services to expand and develop the existing Buenavista mine facilities and infrastructure. The new facilities include a complete copper concentrator and moly circuit that process 100,000 Metric Tons per Day (MTPD) of copper-molybdenum ore, and produce 1,500 MTPD of copper concentrate and approximately 12 MTPD of moly concentrate. The plant reached full production mid-year of 2015.

The new concentrator is a conventional crushing circuit which consists of a gyratory primary, secondary and tertiary crushing circuit that feeds 6 ball mills and a copper-moly flotation, thickening and filtering circuit. M3 is currently working on an optimization and expansion project to process 120,000 MTPD.

The 4 primary crusher building is a unique installation in that it integrates the 2 primary crushers for the concentrator with the 2 primary crushers for the leachable ore system under one common structure.

Construction of Concentradora No. 2 posed various challenges which included minimizing disruption to the existing processing plant, coordinating with its current operations team, and dealing with the numerous on-going capital, maintenance and infrastructure improvements throughout the property.

EPCM services were directed by M3’s staff working closely with the Owners personnel to achieve efficient and orderly implementation of the Project. M3 was responsible for management and control of the various project activities and ensuring that the team had appropriate resources to accomplish the Owner’s objectives.


The underground Mercedes Gold and Silver Mine is located in difficult mountainous terrain near Magdalena de Kino in Sonora, Mexico.

The challenging terrain surrounding this high grade ore deposit complicated construction design and required M3 to create a compact plant that required very little real estate.

M3 took care of the groundwork, acquiring permits and carrying out land negotiations to build the plant and install 70 km of high voltage power lines and 20 km in mine and access roads. The company also supervised the construction of the tailings dam and detoxification plant.  M3 used best practices for environmental care, reducing negative environmental impact and applying strict quality control measures.

The rich ore deposit, with estimated metallurgic recoveries of 95% gold and 30% silver, lead to early discussions of a plant expansion before construction of the mine was completed, something that is very rare and usually done years after project completion.

M3 finished the mine approximately 10% under budget and started production ahead of schedule all the while maintaining good safety, environmental and quality control standards.

Piedras Verdes

The Piedras Verdes Project is a grass roots leach, solvent extraction and electrowinning (SX-EW) copper project located near the town of Alamos, approximately 370 km south of Hermosillo Sonora, Mexico. Total cost of construction is approximately 100 million dollars.

The facility is designed to produce approximately 70 million pounds of copper annually from approximately 40,000 tonnes per day of run of mine (ROM) ore. In addition to the process facilities, the design includes a well field for fresh water supply, a 5 km 115 kV power transmission line and access road to the site, as well as all support facilities required to operate the mine.

This highly efficient mineral processing plant was completed in sixteen months. From design to start up, this fast track project is operational due to the well-coordinated efforts of the client and M3.

San José

The San Jose project is an underground silver and gold mine located in the state of Oaxaca, Mexico.

The Engineering, Procurement and Construction Management (EPCM) performed by M3 includes the design of the grinding and flotation facilities, which are capable of processing 1,500 dry metric tons per day (tpd).  The process plant is comprised of a mobile crushing circuit that yields ore sized to 9 millimeters in diameter, a grinding circuit that yields a 74 micron particle size, a flotation circuit with primary and cleaning stages that produce the silver concentrate, a 6-meter-diameter thickening system and a filtration system that delivers the final concentrate.

The process plant is complemented by a hydraulic refill plant that prepares tailings material in order to refill the underground mine.

The design of the ancillary buildings was also part of the M3 scope, which included a residual water treatment plant, a diesel station, a metallurgy laboratory, administrative buildings, bath and dressing rooms, storage and two workshops.


M3 was responsible for the Engineering, Procurement and site engineering/construction management assistance for the Refugio re-opening project. The Refugio project is a Gold mine located on the Andes Cordillera near Copiapó, Chile with a total cost of construction of 140 million dollars.

The Refugio Re-opening Project consisted of the modification of the existing overland conveyor from primary to secondary crushing plants, adding one conveyor drive-transfer tower, modifying one existing conveyor drive tower, upgraded dust collection system, added a screening building and associated conveyors, and replaced two secondary crushers.  All these modifications increased crushing processing plant capacity from the originally designed 30,000 tonne of ore per day to a 40,000 tonne of ore per day.

The existing power plant was replaced as the main power source with a new 135kM, 110kV power line from Copiapó to the site thereby eliminating the need to haul diesel fuel on an unpaved mountain road. Site conditions made this project very challenging since the project is located at an elevation of 14,500 ft above sea level with very strong wind conditions.

Hecla Greens Creek

M3 has provided on-going Engineering, Procurement and Construction Management services for the Greens Creek Mine since 1995.  This remote lead, zinc and gold mine located at Admiralty Island, Alaska and situated on USFS Natural Wilderness land has unique challenges.  All items consumed at the mine, including construction materials, are barged in from Seattle, WA or Juneau, AK. Concentrate leaves the island via ocean going ships.  The cold wet weather is always a factor for design and construction.

The metal recovery plant started at 1,000 tons per day (TPD) capacity in 1995, and through implementation of M3 projects, has been upgraded to 2,500 TPD capacity. The projects completed include re-opening of surface facilities, water treatment, site housing, concentrate ship load-out, surface water collection and treatment, plant expansion and more.

Campo Morado

This subterranean mine is located high in the extremely remote and steep terrain of the mountains between Mexico City and Acapulco.

M3 initiated its Engineering, Procurement, Construction Management (EPCM) duties at the high grade ore deposit of silver, lead, zinc and gold by putting in infrastructure that included construction roads and new power lines. M3 also carried out socioeconomic integration work with the local communities who had never seen activity of such magnitude.

The mine, which has a capacity of 1,800 tons per day, was brought to production in just four years.

Polymetallic deposits located at Campo Morado are very difficult to process.  Initially, this made the project cost prohibitive.  However, a cost-saving approach was implemented that involved a cheaper plant, built to process the highest grade zinc first, in order to generate income before expanding to the remaining ores. In order to increase the recoveries, the material was also turned into a much finer grind than is typical.

M3 also prepared the capital investment estimate, the pre-feasibility study, assisted with the process plant start-up and finished the project significantly under budget.

Alamo Dorado

Álamo Dorado, the first commercial plant in the world to use direct electrowinning of silver solution, is 25 miles southeast of the town of Álamos in Sonora, Mexico.  This open pit mine reclaims silver through agitated leaching and is capable of processing more than 5,000 tons per day.

M3 carried out the Engineering, Procurement and Construction Management for this mine.  This work included designing the plant that executes the new direct electrowinning process, purchasing the equipment for the crusher and SAG mill, and assisting with project start-up.

Direct electrowinning of silver solution is a simpler process for extracting silver that was possible to implement due to the characteristics of the rock on site and the unique design developed by M3.

The facility’s Acidification-Volatilization-Reabsorption (AVR) cyanide reclaiming process produces safer tailings while at the same time improving efficiency by recycling this reagent for future use.

Other innovative and environmentally friendly ideas were also executed at the mine, including the use of belt filters to facilitate dry tailings disposal and water conservation.

Francisco I. Madero

This underground mine located in central Mexico near the state of Zacatecas, commissioned one of the largest SAG Mills in Mexico at the time of its installation. The plant is designed to process 8,000 tons per day.

The mine produces two ore types; a lead-zinc ore with silver credits, and a copper-silver ore.  To boost flexibility and as a cost-saving measure, the mill circuit was designed to process either ore type through individual treatment.  When copper-silver ore is processed, the lead circuit is bypassed and the zinc circuit is used for copper concentrate production. Concentrates are shipped to the Peñoles smelter in Torreón.

M3 prepared preliminary and feasibility studies for the project and assisted with the purchasing, construction management, start-up and run-in. M3 engineers also operated the control system for the first three months of operations, including commissioning of the expert system.