St. Marys Cement Plant

Location: St Marys, Ontario, Canada
Owner/Operator: St Marys Cement Group

St Marys Cement Group is one of the oldest cement companies in North America. It was established in St Marys, Ontario, in 1912 and is a leading manufacturer of cement and related construction products in Canada and the United States. St Marys operates two cement plants in Ontario. The St. Mary’s cement plant  is the largest employer in St. Marys, Ontario. The plant produces cement from limestone that is abundant in the region, clay and various other materials.

HGC Engineering was retained by St. Marys Cement Group  to undertake an acoustic assessment of their St. Marys facility. The study was required in support of an application to the Ministry of Environment (“MOE”) for an Amended Environmental Compliance Approval (formerly Certificate of Approval). The assessment considered all existing operable sound sources at the facility, as well as sources associated with an alternative fuel feed system which was under an MOE sanctioned trial at the time of the study.

Facility Description:
The site operates 24 hours per day, 7 days per week. Various raw materials, including petcoke, fly ash and sand, are brought to the site via trucks. Limestone conveyed to the cement plant from an adjacent quarry is stored in surge piles and further processed above grade by a secondary crusher and a screener, both of which are enclosed in outbuildings, following which the limestone is conveyed to silos for storage.

The material is then processed through a raw mill which grinds and mixes the material to a uniform particle size, while employing hot exhaust gases from the pre-heater tower to dry the “raw meal”, which is then stored in the kiln feed silo. The raw meal is then fed into the kiln, which is fuelled by petroleum coke (“petcoke”) that is processed in the fuel mill building. Material exiting the kiln, referred to as “clinker”, is pre-ground in a roll press before being transferred either to storage or to the finish mill building where the final product, cement powder, is produced by grinding the clinker in a ball mill with limestone and gypsum.

The cement powder is conveyed to storage silos on the north side of the site, from which it is either loaded directly into bulk tanker trucks or into bags for offsite delivery. Noise sources associated with below-grade quarry operations adjoining this site are covered under an aggregate license from the Ministry of Natural Resources and were not included in our assessment.

Acoustic Assessment:
HGC Engineering conducted comprehensive onsite measurements of more than 200 individual sources of noise using superior sound intensity  instrumentation and measurement techniques.

A 3D acoustical model of the site and surrounding area was developed, to which the source measurement data was input in order to predict the individual contribution of each noise source to the overall sound levels of the site in the surrounding community. These overall sound levels were confirmed through direct measurement at the nearest points of reception and compared to the applicable limits, established in accordance with MOE guidelines. Detailed noise control recommendations and a Noise Abatement Action Plan were developed by HGC Engineering and incorporated into an Acoustic Assessment Report for the site.

The primary sound sources at the facility that were evaluated:

• Surge pile
• Secondary crusher & screen
• Kiln shell cooling fans & clinker cooler
• Kiln stack
• Finish mill dust collector exhausts
• Shipping equipment (road trucks)
• Emergency generator
• Portable crusher & screener

Acoustical Engineering Services Included:

• Comprehensive onsite and offsite acoustical measurements
• Predictive acoustical modeling
• Noise control recommendations
• Acoustic Assessment Report & Noise Abatement Action Plan