Omya in Vermont

Tailings Management

TAILINGS MANAGEMENT

On May 8, 2009, Omya submitted to the Vermont Agency of Natural Resources (ANR) an application for a 5-year Full Certification to manage its tailings operations. A Full Certification by the ANR provides Omya with a long-term solution to managing its tailings operations in an engineered lined Tailings Management Facility (TMF) located on its site in Florence.

During the Full Certification application process, Omya will continue to manage its tailings and monitor the site in accordance with all the conditions and requirements of the current Interim Certification (IC) issued in October 2008 by the ANR. The IC allows the company to manage its tailings at its site in Florence for a two year period [subject to renewal for an additional two years]. Our early submittal of the application allows the necessary time for a thorough review, approval, and construction of the TMF before the expiration of the IC in October 2010.

If you have interest beyond the brief explanations provided here, please review the complete Full Certification Application by clicking on the following links: (NOTE: File sizes are large, and may take time to open or download)

05.08.09 Full Certification Application Part A Administrative (8,000KB).
05.08.09 Part B Site Characterization (33,000KB).
05.08.09 Part C Engineering Design (40,000KB).
05.08.09 Part C-4 Engineering Drawings (17MB).
05.08.09 Part D Operational Information (904KB).

The following Draft Solid Waste Certification Reports were presented at an Environmental Stakeholder Meeting on January 13, 2010 by Sanborn Head & Associates.

12.18.09 Solid Waste Disposal Facility Draft Certification (82KB)
12.18.09 Solid Waste Disposal Facility Draft Certification Fact Sheet (89KB)

The following report was presented at an Environmental Stakeholder Meeting on June 30, 2009 by Sanborn Head & Associates.

06.30.09 Tailings Management Certification Application Presentation (8MB)

The Interim Certification, which allows Omya a two-year period to continue to manage its tailings under Vermont’s solid waste management regulations, was issued in October 2008 by the Vermont Agency of Natural Resources. To review the complete Interim Certification click on the following link:

10.21.08 Interim Certification (780KB).

WHAT ARE TAILINGS PRODUCT?

Tailings material is a by-product resulting from Omya’s mineral processing operations, similar to most other mineral processing operations. Because the material that is extracted from the quarry contains mineral impurities, these impurities must be removed to enable Omya to obtain calcium carbontate that is nearly pure. To do this, during processing, a flotation agent (TOHI – Tall Oil Hydroxyethyl Imidazoline based) is added to the process slurry and air is introduced. The introduction of air causes bubbles to form. Mineral impurities that naturally occur in the quarry stone (chlorite, plagioclase, feldspar, quartz, and mica) attach to the bubbles and float to the surface. Because calcium carbonate is not attracted to the flotation agent, it does not float to the surface but rather settles to the bottom of the flotation tank and is removed for further processing. The mineral impurities are skimmed off the top, transported to settling basins, and, once dewatered, are deposited into the tailing management areas in solid form. Physically, the tailings product resemble a sandy silt material.

A tailings characterization study (192KB) confirms that the tailings are comprised almost entirely of natural minerals, including calcium carbonate that is not separated from the mineral impurities. The non-mineral components found in the tailings product are from compounds added during the flotation process and are not present in quantities that cause harm to the environment or to human health.

HOW IS THE MATERIAL BEING MANAGED AT THE PLANT SITE?

Tailings product have been retained in Tailings Management Areas (TMAs) located at on-site quarry areas for almost thirty years. The tailings product are maintained on site in order to be able either to reclaim the calcium carbonate remaining in the tailings product or to find a market for it. To date, the technology has not been refined to enable broad-scale reclamation and re-use of the calcium carbonate content nor has Omya yet been successful at its efforts to find large-scale alternative uses for the tailings product.

Economically viable markets for the tailings product are being sought actively, and the technology to recapture and reduce the calcium carbonate content of the tailings product continues to be developed.

IS THE MATERIAL SAFE?

Yes. Extensive scientific and technical investigations (192KB) confirm that the tailings do not produce an environmental or public health threat . Tests performed and supporting that conclusion have included tailings characterization, toxicological assessments, groundwater modeling, and geological surveying.

Only a very small percentage, a fraction of 1%, of the tailings product are composed of non-mineral substances, which include TOHI – the process additive used to separate pure calcium carbonate from the other minerals naturally occurring in the marble ore.

DOES OMYA TEST ITS TAILINGS PRODUCT?

Yes. The most recent tailing product characterization (192KB) was completed in June of 2005. Omya is publishing these tests here and invites you to review those tests to fully acquaint yourself with the results of that analysis.

HOW IS THIS MATERIAL REGULATED BY THE STATE?

Omya’s tailings product, and management thereof, has been regulated for almost thirty years under Act 250. In addition, following the conclusion that the tailings product constitutes a solid waste, on August 15, 2005, Omya filed an application for Interim Certification for the management of the material as a solid waste. Once approved by the Agency of Natural Resources, Interim Certification will enable the company to continue its operations for two years while alternative methods for management are pursued, along with continuing efforts to market the tailings product. In addition, the Agency of Natural Resources is promulgating new rules for the management of mining wastes that may be applicable to future operations.

Omya has conducted, and will continue to perform, extensive analyses of the tailings management processes. To date, the studies demonstrate that the tailings product cause no harm to the environment or to public health.

HOW DOES OMYA PLAN TO REDUCE THE AMOUNT OF ITS TAILINGS PRODUCT?

Reduction of the volume of tailings product is an on-going goal. Since Omya began production at the Verpol plant in 1979, it has worked to improve ore management and its flotation process. These improvements have reduced the generation rate of tailings product and reduced the relative amount of process water used at the plant.

RELEVANT LINKS

Definitions

02.19.08 – Existing Tailings Management Areas Life Cycle Report (1.8MB)

08.15.05 – Tailings Characterization Report (192KB)

08.15.05 – Interim Certification Application (39.7MB).

Correspondence Related to the Interim Certification Application