Code of practice for managing particulate matter emissions in the potash sector: chapter 1

Official title: Code of practice for the management of PM_2.5 emissions in the potash sector in Canada

1. Introduction

Potash fertilizer production is a major industry in Canada, ranking first worldwide with a capacity of approximately 30 million tonnes in 2016 (37% of global capacity). Potash mining in Canada is carried out by means of two distinct methods, conventional underground mining and solution mining. Conventional mining is the process of tunneling below the earth and removing ore deposits from the mine’s walls. Solution mining is an alternative method where unsaturated brine is injected into the ore deposit through wells to dissolve potassium chloride (KCl), and when saturated this brine is pumped to the surface for processing. The major processing activities, drying and compacting, are the primary sources of fine particulate matter (PM_2.5) emissions from this sector. Less significant sources include mine air exhaust (from conventional mining only), the use of diesel trucks, crushing, screening, loadout, and fugitive sources.

Federal, provincial and territorial environment ministers are taking action to better protect human health and the environment by endorsing and implementing the new Air Quality Management System (AQMS). The AQMS includes Canadian Ambient Air Quality Standards for fine particulate matter and ground-level ozone, base level industrial emissions requirements (BLIERs) and local air zone management by the provincial/territorial jurisdictions

Fine particulate matter with a mean aerodynamic diameter of less than 2.5 microns (PM_2.5) is a significant air pollutant in the potash sector. The BLIERs process examined all sources and controls of PM_2.5 emissions from potash facilities and concluded that a PM_2.5 emissions code of practice (code) was the most suitable instrument for the control of PM_2.5 emissions in this sector.

Annual PM_2.5 emissions in the Canadian potash industry have ranged between 785 and 1643 tonnes/year over the 3-year period 2008-2010, and represent 1.8% of total industrial emissions.

1.1 Sector description

Potash is a generic term used to describe a variety of minerals and manufactured chemicals containing potassium, a basic nutrient for plants. Potash ore is comprised of approximately 40% KCl, 55% sodium chloride (NaCl) and 5% insoluble material. It is a limited resource that is found in only a few countries around the world. Canada accounts for almost half of global potash reserves, of which a significant portion is found in the Prairie Evaporite Deposit in Saskatchewan.

In 2016, Canada’s potash industry consisted of three companies with a combined 11 facilities, of which 10 are in Saskatchewan and one in New Brunswick. Due to market pressures the facility in New Brunswick was placed on care and maintenance in January 2016. Currently, eight conventional underground mines and two solution mines operate in Canada. These operations are explained in detail in Section 2.

On a company basis, in 2016 Potash Corporation of Saskatchewan (PCS) possessed 53% of the potash capacity in Canada, with Mosaic at 39% and Agrium at 8%. All current Canadian potash producers have completed or are in the midst of completing capacity expansions for their operations. There is also significant activity related to potential new producers of potash in Canada, especially the new entrant K+S Potash Canada which expects to be producing in 2017.

Canada’s production in 2014 was estimated at 18.7 million tonnes. The majority of Canadian potash is exported, estimated at approximately 98% of production. More than 50% of Canada’s potash exports are shipped to the United States, followed by Brazil, Indonesia, China, and India.

1.2 Objective and scope of the code

The overall objective of the code is to identify and promote best practices in the Canadian potash industry, in particular with respect to PM_2.5 emissions. Adoption of best practices will facilitate continual improvement in environmental performance in the sector. The code applies to environmental aspects of potash production and to best practices to control PM_2.5 emissions, most of which originate from the drying and compacting processes.

The code was developed as part of the qualitative BLIERs of Environment and Climate Change Canada’s AQMS policy. The code does not recommend that existing facilities require major technological changes. However, in the design of new facilites, more current and effective technologies should be considered to further minimize emissions. The Code also recognizes that no one control technology is universally appropriate for every application due to the variability and uniqueness in operating conditions from site to site and between various processes within each site.

The recommendations in this code should be applied where and when appropriate based on the particular circumstances of each facility. Consequently, the code does not aim to quantify the effect that each recommendation would have on PM_2.5 emissions. Rather, it should be considered a basic tool for developing a program of good practices by the facilities without imposing regulatory constraints. Conversely, the recommendations made herein do not reduce the scope or application of the legal requirements of municipal, provincial, and federal governments.

1.3 Code development

The code was developed by Environment and Climate Change Canada in consultation with the governments of Saskatchewan and New Brunswick and the potash industry.

Environmental management practices recommended by various national and international organizations were reviewed and incorporated. Information on best management practices was drawn from various sources such as consulting reports, literature and environmental codes by provinces/territories, Environment Canada and the United States Environmental Protection Agency (U.S. EPA), as well as from individual potash companies and technical journals. Three consulting reports in particular, the Hatch foundation report^Footnote 1, the Cheminfo PM report^Footnote 2, and the Province of Saskatchewan’s Potash Mining Supply Chain Requirement Guide^Footnote 3 provided the basis of this code.

A specific approach that was used in the formulation of this Code was developed in the 1990s by the U.S. EPA. It is founded on the principle that emission-control devices that are well monitored and maintained operate at their optimum design efficiencies. This approach is referred to as compliance assurance monitoring (CAM), and provides facility operators with an indication of the most efficient operation of emission control devices. The CAM philosophy establishes enhanced monitoring of significant emission units that use control devices, by:

• documenting continued operation of the control devices within ranges of specified indicators of performance that are designed to provide a reasonable assurance of compliance with applicable requirements
• indicating any excursions from these ranges and
• allowing the operator to respond to the data so that the excursions are corrected^Footnote 4

1.4 Code structure

The code describes the sector’s mining and processing activities in Section 2. Section 3 discusses the PM_2.5 emissions produced by these activities. The recommended work practices intended to control these emissions are set out in Section 4. Finally, Section 5 provides a general approach to the implementation of the code.