Specialist underground mining and metallurgical processing services company, UMS Group (UMS), is proving the success of its integrated partnership business model on the Ero Copper Caraíba Operations Pilar Underground Mine Deepening Project in the state of Bahia in Brazil. UMS has drawn on expertise from its multi-disciplinary businesses to provide engineering design, procurement and contracting services for a new underground vertical shaft system.

Robert Hull, COO of UMS Group, says that the Pilar Mine project demonstrates how UMS can add true value through close collaboration with the client across all stages of a project, from the front-end through to construction, and bringing production forward compared to a conventional project.

Introduction

Ero Brasil (previously Mineração Caraíba S.A. or MCSA) has been operating the Pilar Mine, part of the company’s Caraíba operations, for nearly 50 years, first as an open pit mine, and then as an underground mine for the last 25 years. Open stoping is the preferred mining method with underground access via a switch-back ramp which is currently used for ingress/egress of personnel and equipment and the hauling of broken ore from the stopes to an underground crusher station, before hoisting of ore via a shallow vertical shaft to surface. On surface the ore reports to the concentrator via a secondary crusher station and stockpiles.

Since the acquisition by the Toronto and New York Stock Exchange dual-listed Ero Copper Corp., there has been a significant investment in exploration at the mine. In 2021, UMS was approached to further optimise shaft sizing for accessing the confirmed and open ore body located 1 500 metres and more below surface, as quickly as possible.

UMS’s engineering technical services arm initiated a trade-off study and, working with the client, determined the optimal design for the size of ore body and production goals would be a four-compartment vertical shaft, 6.3 metres in diameter with two double-drum winders – one dedicated to ore/waste hoisting and the second dedicated to personnel raising/lowering. With this design, the mine would effectively meet its desired production of 2.2 Mtpa (million tonnes per annum).

With support from the client, UMS’s engineering and contracting teams immediately commenced with engineering design, capital cost estimation and project schedule of the shaft system including the procurement phase, which formed an integral component for the broader feasibility study conducted by NCL of Chile, including the deeper underground mine design and optimised development/production schedule.

Communication and logistics

Brad Rip, Project Director at UMS, says that UMS began working on the feasibility study just as South Africa went into the COVID-19-induced ‘working from home’ phases. With UMS having previously adopted digital communication technology, this provided a crucial platform for cross-team and cross-continental collaboration that enabled the project to continue regardless of locations and time zones. This proved invaluable beyond the pandemic as all progress meetings and document sharing are still managed digitally, bringing together people from the site, the Johannesburg office, the owner’s team in Brazil, and fabricators in South Africa and Brazil.

By mid-2022, a Brazilian civil contractor had been appointed, as well as other long-lead suppliers such as the steel fabricator for the headframe and other steelwork including the winder house.

In order to de-risk fabrication requirements, UMS and the client agreed that all critical and specialist equipment such as the shaft drill-rig, loaders, winders, hoisting ropes, rope attachments and safety devices were sourced from suppliers in South Africa who had experience in fabricating these items. This meant shipping the items to the port of Salvador in Brazil, before transferring by truck some 500 km to the Pilar Mine site.

“Although Brazil is a well-established mining country, the majority are surface mines and there is no locally available specialist equipment for shaft sinking, so logistics management has been a significant part of the project. This has proved quite successful with the ERO Brasil Commercial Department being a key player in ensuring the importation of equipment has gone as smoothly as possible,” says Rip.

Latest developments

By the end of 2022 and into the first quarter of 2023, UMS started to mobilise on site, while the first shipping consignment, comprising the personnel winder which will also serve as the kibble winder, 16 containers and 20 break-bulk items arrived on site. With the structural civils at an advanced stage by this time, the installation commenced almost immediately. At the same time, steel erection commenced with the headframe and winder-house assembly, and the site began to take on a construction site appearance.

At the time of writing, the stage winder has arrived on site as well as numerous other items of specialist equipment such as the drill-rig and loading units that will temporarily be used for shaft sinking. Once it has been decommissioned, this stage winder will be returned to South Africa or to UMS’ next project and will be replaced with a new rock hoist winder to be procured by the client.  

Rip reports that the first blast at the bottom of the collar took place in mid-April this year and the UMS team has been building up to get the drill, blast, muck, and support cycle up to the desired cycle-time.

Meanwhile, the engineering and procurement team in South Africa is continuing to work on the design and tenders for the underground rock (ore and waste) handling systems. It is the intention to procure the equipment including rock breakers, feeders, crushers, conveyors, and fabricated bulkheads from established Brazilian suppliers and fabricators and to appoint Brazilian electro-mechanical erectors to install the systems.

He explains that because the underground mine has been in operation for some 25 years, there is already a trackless switch-back ramp that goes down to nearly 1 000 metres below surface. This has provided the opportunity to raise-bore a vertical hole in the centre of the shaft from certain points underground to the surface to expedite the shaft sinking process through a slipe-and-line method. He adds that UMS has however allowed for a rapid transition to conventional blind sinking should this be required so as not to delay the project.

Local presence and collaboration

Hull says that to facilitate this project, and future ones in South America, UMS has established a local company, UMS Brazil, and appointed local staff including a country manager, Bruno Paladino. “Bruno has been instrumental in delivering this project and helping us quickly get to grips with the Brazilian legal, commercial, and financial systems.”

“Everyone involved has pulled together to get the job done, going over and above what is required of them. We are also grateful to the owner’s team for their assistance in helping us navigate the logistical challenges, the local business modus operandi, and the country’s safety legislation. Collaboration is key to the success of this project, and we are pleased to have been very warmly welcomed in Brazil by all parties involved as well as the community and contractors,” says Hull.

UMS is working closely with the client to transfer skills to local contractors and suppliers, many of whom are working on a shaft sinking project for the first time.

Expanding UMS’s footprint in South America

“We are fast establishing a track record in Brazil, familiarising ourselves with local business policies, and building relationships with local suppliers,” comments Hull. “We now have the capabilities to expand further into Brazil as well as into other South American countries in partnership with other companies looking to expand their mining operations underground.

UMS has recently acquired two large deep level winders in Chile to add to its global growing fleet of winders. The winders are well suited to South American sinking conditions and can be deployed quickly within the region. The winders have the ability to sink to depths of over 1500 meters.

“We are in a unique position that we can bridge the gap between the front-end engineering and design and construction of a project to get it delivered quicker for the client”, concludes Hull.