Revitalising St Marys Cement

The resurgence in the US cement market in 2014 prompted Votorantim Cimentos-owned St Marys Cement to launch a modernisation and expansion programme of its plant in Charlevoix, Michigan, USA.

A leading supplier of cement throughout the Great Lakes region, Votorantim Cimentos’ St Marys Cement officials say the 1200-acre Charlevoix site is well worth the US$186m invested in upgrades that will expand plant capacity by 40 per cent. Boosting cement output from 1.4Mta to 2.1Mta on the back of a quarry that holds reserves for a further 70 years, the revitalisation of the plant’s systems and equipment enables the cement producer to take full advantage of new technologies for efficient operation and superior environmental control.

Continued investment

The Charlevoix plant first opened in 1967 as a wet-process kiln operated by the Medusa Cement Co. In the late 1970s, Crane Co, a holding company based in Stamford, Connecticut, took over the facility from Medusa and eventually converted it into a preheater/precalciner dry-process operation in 1979. Cemex acquired the facility in the late 1990s, operating it for several years before selling it in 2005 to St Marys Cement. Soon after purchasing the plant, St Marys invested some US$20m in new environmental controls and other capital improvements.

State-of-the-art improvements for streamlined operations

The latest, much-needed, modernisation improves the raw mill, main pyroprocessing line, finish and coal mills, reflecting the considerable changes of the past 40 years, says Celso Martini, vice president of cement operations at Votorantim Cimentos North America.

“We are making a significant investment in efficiency and environmental control improvements,” Mr Martini explains. “All modifications represent a major upgrade in technology and efficiency, so we are building a state-of-the-art operation with the very latest in manufacturing technologies and environmental controls.”

The plant modernisation encompasses:
• a raw mill upgrade, modernised with an all-new 3900hp dorol roller mill designed by thyssenkrupp Industrial Solutions (TKIS) with a capacity of 445tph, and equipped with a new dynamic separator and dedusting cyclones. The mill circuit includes a new 5200hp system fan.
• an upgraded preheater/precalciner, designed by TKIS, modernised with the addition of a parallel four-stage string to the existing four-stage preheater tower, increasing the feed capacity by 40 per cent. A 1750hp induced-draught fan is included in the new preheater string.
• a new calciner, designed by TKIS, replaces the old flash furnace calciner, ensuring increased residence time to 7s at temperature while providing more efficient combustion and reducing plant emissions.
• a new 25,000t capacity tangential blending silo, designed by TKIS, to store and distribute the kiln feed, greatly improving quality control and reducing power consumption. The upgraded system replaces a 9000t kiln feed storage system.
• kiln modifications that increase capacity from 4250tpd to 6000tpd. The modified kiln is 5.2m in diameter and 73m long.
• a state-of-the-art Polytrack clinker cooler from TKIS, with technology and efficiencies that produce a cooler kiln product and enhance heat recovery.
• a new 6000hp cement ball mill rated at 120tph, designed by China-based TCDRI. Added to the existing three mills, it provides capacity to handle the overall production increases.
• a new 2700hp high-capacity coal mill rated at 38tph, designed by TCDRI. The plant operates on petcoke and coal, supplemented with five per cent shredded plastic that would otherwise end up in landfill.
• a new clinker transport conveyor to move clinker to the finish mills.
• a new cement transport gravity conveyor and elevator to move cement to the storage silos, installed with the new cement mill. The system provides an energy- and maintenance-efficient alternative to conventional pneumatic systems.

Multi-year project brings peak workforce of 400 to the local economy

“Throughout the project we followed an aggressive but realistic schedule that helped us make measured and meaningful progress while keeping a sharp focus on safety for everyone on site,” Mr Martini says. “As things moved forward we devoted more time to engineering activities and adjusted the equipment delivery schedules accordingly. The challenges of construction in northern Michigan, including harsh winter weather, also played a role in determining how quickly things progressed.”

Phase one of the project included construction of the new roller mill, site civil work and foundations, and installation of the new blending silo. The roller mill installation, managed by general contractor Walbridge, a Detroit-based construction firm, was completed in April 2017 and successful commissioning of the new mill circuit took place in May that year. Christman Construction of Grand Rapids, Michigan, completed site civil work, including foundations for the new preheater tower, the modified kiln, clinker cooler, coal mill, cement mill, and various transport systems required by the modernisation. Pierson Construction Inc of Columbia, Missouri, also completed construction of a 25,000t concrete kiln feed storage silo during Phase one.

Phase two started in early 2017 under the direction of Vezèr’s Precision Industrial Constructors of California, general contractor for all the remaining elements, including the preheater tower, kiln, finish mill, coal mill and conveyor systems. Several local contractors assisted the general contractors during the project, including Strand Construction, IPEC, MDC Construction, Reith Riley, Northern Industrial, John E Green, Versatile Construction, Alpine Electric and Newkirk Electric.

Votorantim Cimentos’ Brazil project team provided overall project management, working closely with the operations team at the Charlevoix plant, with additional support from Wood Plc’s Atlanta office. Brazil-based engineers also provided remote support. The Safety Management Group of Indianapolis provided supplementary safety consulting for the project.

The project has brought more than 600 workers to the Charlevoix area. At its peak, the additional reconstruction workforce on site reached 400, providing challenges that were formidable yet manageable, Mr Martini says.

“Keeping the existing plant running in the midst of active construction was tricky,” he acknowledges. “We worked hard to keep our 132 full-time employees up-to-date while ensuring everyone’s safety during the process.” He is proud to report that there were no lost-time injuries (LTIs) throughout the multi-year project, which clocked up more than 840,000 working hours.

The influx of skilled labour has been good for the local economy. “We’ve seen the area benefit from the extra people in town,” says Charlevoix township supervisor, Chuck Center. “Previously they projected that 100-200 contractors would be coming in, but those numbers have certainly been much higher, which is great for us.” Charlevoix has a permanent population of 2500. The modernised plant will also provide up to 10 new full-time positions.

Investing in sustainability

The Charlevoix renovation reflects a longstanding commitment to environmental protection on the part of Votorantim Cimentos and St Marys Cement. The company’s US$20m investment in 2005 included the installation of silencers and pollution controls to reduce noise and air emissions.

Company officials also worked with Michigan’s Department of Natural Resources on a fish-stocking programme for chinook fingerlings and created nesting areas for bald eagles. In 2006 these efforts earned St Marys the Portland Cement Association’s Overall Environmental Excellence Award, which acknowledged the plant’s proximity to residential areas and the company’s clear commitment to improving the local quality of life.

Approximately US$29m – or about 17 per cent of the current revitalisation budget – is devoted to environmental and pollution control improvements. As a result of plant refurbishments:
• Overall fuel consumption will decrease by 11 per cent.
• Power consumption will decrease by 10 per cent.
• SOx and NOx  emissions will be significantly reduced.
• All NESHAP emissions standards will be met.

End-of-April countdown to new systems 

With most construction nearly complete, the plant is expected to shut down for commissioning this spring.

“The plan is to tie everything together in about 30 days,” says Mr Martini. “The new cooler, tower, the blending silo and the modified kiln will all be brought on online. We anticipate being fully operational by June.”

Recently-built storage domes in Charlevoix and the Calumet City terminal near Chicago added 130,000t of storage capacity to the system and will easily handle increased production from the modernised plant.

The company is also investing US$45m to add a new vessel to its Great Lakes fleet, converting an open-topped barge built in 1957 to a self-unloading cement carrier. The refit will add 45m (150ft) feet in length and install an entirely new bow, spar deck and hatch covers. “Around 95 per cent of our product is shipped via Lake Michigan,” explains Mr Martini. “Adding a third ship to the fleet will help us to use our new production capacity to better serve our customers.”

The vessel, with its 14,000t capacity, is expected to join the St Marys Lake Michigan fleet in late November 2018.

“Our investment in Charlevoix reflects our commitment to improve all aspects of our operations there and to ensure St Marys’ future in the local business community,” Mr Martini says. “These efforts are consistent with Votorantim Cimentos’ commitment to operational excellence in cement manufacturing, ready-mixed concrete and aggregate production worldwide.”

“The organisation’s motto – Life is Made to Last – expresses the desire to have a positive impact on people and the planet,” he adds. “Managing our environmental impact in the communities where we work is an essential part of our business model.” 

This article was first published in International Cement Review in May 2018.