Proposed Gypsum Stack Extension
Questions and Answers - July 8, 2002

This is a “living document” and we will be adding questions and answers and sharing with our neighbors and community, by mail outs (sign ups from the Open House) and posting to this website.

Size and Location
Q.	How big will it be in comparison to what it is now?
A.	The current gypsum stack and cooling ponds cover about 425 acres. The stack extension will be constructed in phases (2004 – 2009) and will ultimately cover an additional 295 acres.
Q.	How far off the highway is this stack going to be?
A.	The stack extension will be about 75 ft (23 meters) further away from the highway than the existing stack to provide for a utility corridor.
Q.	What is the land currently being used for?
A.	The land is currently in agricultural use.  Crops being grown vary from hay to peas, and cereals.
Q.	What will happen to the road that is there now?  Who decides?
A.	The existing road will be closed.  If deemed necessary by county officials and the affected landowners, a new road will be constructed further to the north.
Future Storage Needs
Q.	For each tonne of fertilizer produced, how much byproduct gypsum is produced?
A.	Although this varies depending on phosphate rock composition, an average amount is 2.4 tonnes of gypsum per tonne of phosphate fertilizer produced.
Q.	When was the last extension of the gypsum stack?
A.	The last extension of the gypsum stack took place in 1996. This 25-acre extension to the southeast is what we call the D-Pond.
Q.	How long will this extension last?
A.	We estimate that the stack extension will extend the available storage on site for about 26 years.
Q.	What is the limit on how high the stack can be, and why is there a limit?
A.	The stack is now about 95 feet (29 meters) high.  The final elevation of the current gypsum stack and gypsum stack extension will be approximately 150 feet (46 meters) above ground level.  As the stack is raised the sides are sloped inwards such that the available surface area decreases by close to 10 acres each year.  The final stack height is limited by both remaining surface area and the safe engineering design, that considers both slope stability and the bearing capacity of the underlying earth.
Q.	What will Agrium do after it has used up all this expanded space?
A.	We estimate the proposed extension will provide storage space for 26 years.  However, we are also actively investigating alternative uses for gypsum that will allow us to make beneficial use of gypsum instead of storing it.  It is expected this will extend the life of the available gypsum storage.  Other storage alternatives will be evaluated in the future.
Q.	Are all of the ponds still active? How long will the old ponds be active?
A.	All of the existing ponds are still active.  Since the outer dyke slopes inward, each year the total surface area decreases as the stack height is increased.  There will be a significant period of time when both the existing stack and the extension area will be active.  This is mainly due to winter conditions, where the cold weather and freezing of the pipeline requires us to use the closer existing stack.  Final closure of the existing stack will take place when the final elevation is reached.
Q.	Can you recover the land afterwards?  What happens in 30 years time?
A.	Ultimately when the stack is closed, the surface will be vegetated.  We are currently conducting growth trials to determine the best strategy for vegetation.  Of course, we will also continue to look at alternative beneficial uses for the gypsum to reduce the need for storage.
Gypsum Alternative Uses
Q.	Is there a market for this material, and what is Agrium doing to investigate this market?
A.	Agrium has been exploring alternative uses for gypsum.  To date alternative uses we have explored have included: 1) Tar sands tailings settling and consolidation - by helping consolidate the very small particles in the tailings pond, gypsum can speed up site clean-up. 2) Manure composting – reduces the odor, controls flies, speeds composting and maintains the nitrogen content. 3) Use on high salinity soil - improves the fertility and makes the soil permeable. 4) Remediation of brine spills at oil and gas well sites – improves soil permeability and decreases salt concentration. 5) Road base construction – due to its compactability and because it makes the top layers impervious to water, gypsum may have value in road construction. 6) Set retarder in the manufacture of cement – by blending gypsum with the rock mixture, gypsum can slow the setting of cement.
Q.	Are there any other long-term alternatives that Agrium could be investigating?
A.	We are continuously looking for alternative uses for our gypsum to minimize waste and maximize beneficial use.  Each time there is a possible use for our gypsum we investigate it thoroughly with Government Agencies such as Alberta Agriculture, Agriculture Canada, and Alberta Environment.  We are presently exploring several alternative uses and we will continue to do so in the future.
Q.	What kind of soils benefit from gypsum applications?
A.	Gypsum is beneficial for uses in soils as both a nutrient and as a soil conditioner.  As a nutrient, soils that are low in calcium and sulphur (e.g., peat soils) will benefit from gypsum applications.  As a soil amendment, soils that have an imbalance in their calcium/sodium ratio, particularly solonetzic and sodic soils (hardpan soils) will benefit from gypsum additions.  Agrium will be providing information to the Canadian Food Inspection Agency (part of Agriculture and Agri-food Canada) so they can review the safety and benefits of phosphogypsum use with the objective of obtaining approval for use of the material as an agricultural supplement.
Q.	Is phosphogypsum toxic?
A.	No.  Hydrated calcium sulphate or phosphogypsum is a byproduct of the production of phosphate fertilizer.  It is acidic because part of the process involves the production of phosphoric acid.  Our workers that work with the material on a regular basis are not required to wear any additional personal protective equipment other than hard hats, safety glasses, and steel-toed boots.  Phosphogypsum has been shown to be a useful additive for manure composting to reduce odor, control flies and improve nitrogen content.  It is also been tested and found very effective as a treatment for high saline soil.  When mixed with mine tailings water, gypsum is very effective at settling small particles to speed clean up.
Q.	Why is some of the gypsum in the stack darker in color?
A.	The color of the gypsum depends on where it came from and the type of rock that was used to make it.   Much of the red color you see comes from iron.
Design features
Q.	Agrium has been operating a stack for well over 30 years now.  What have you learned and what are you changing in this design because of those learnings?
A.	Best practice with respect to gypsum stack construction has evolved since the first stack was constructed on the site in 1969.  We will be using best available technology and design practices for constructing the gypsum stack extension.  Our current stack has a natural clay till liner; our stack extension will have a dual liner system (natural clay till liner plus a heavy duty synthetic liner) and an underdrain system.
Q.	How will the runoff from rain and snow be handled?  What about drainage from the stack?
A.	Surface runoff and drainage from the stack will be collected in a perimeter ditch system and used in the phosphate production process to conserve water for reuse and to protect the groundwater.
Q.	What about groundwater impacts?
A.	The proposed gypsum stack extension is designed with a state-of-the-art dual liner system.  The first layer is a two-foot (0.6 meter) minimum thickness natural clay till clay liner.  The second is a heavy-duty synthetic liner to further protect the groundwater.  Additional monitoring wells will also be installed around the extension area to detect any possible impacts to groundwater quality from our operations.
Q.	Does the current stack leak?  How are you retrieving that leakage?
A.	We do have seepage from the existing stack.  In order to limit the impacts to groundwater, the existing gypsum stack has been surrounded by a groundwater intercept system.  This system, which surrounds the existing gyp stack, works like the weeping tile around most houses.  We continue to monitor the existing stack for seepage using a system of groundwater monitoring wells as well.
Q.	Has this leakage affected groundwater that is used as a drinking water source?
A.	Twice per year, Alberta Research Council samples and tests the drinking water of our neighbors on the west side of the river.  We share these results with our neighbors and to date there has been no impact to their drinking water.  We continue to monitor the groundwater impacts of our operation and to use intercept wells to minimize those impacts.
Q.	Is the old stack lined?
A.	Most of the current stack has a natural clay liner.  The newest extension known as the D pond has a clay liner but not a synthetic liner.  The proposed extension will have both a natural clay till liner and a synthetic liner to protect groundwater.
Q.	How will you know if your liner leaks?
A.	We believe that our new double liner system is state of the art and very reliable.  However, we will install additional groundwater monitoring wells around the extension area as a safeguard to detect potential impacts to groundwater.
Q.	Will the extension change groundwater flows resulting in groundwater mounding or standing water?
A.	This is one of the issues we are currently investigating in consultation with Alberta Environment.  We have hired experts in hydrogeology to perform computer modeling of the groundwater flows to determine any potential impacts from the proposed extension.
Q.	How will you ensure the integrity of the liners?
A.	Inspection and quality control procedures will be in place during construction to ensure the integrity of the liners.  We are using best control technology and practices to limit the chance of leakage. If some portion of the synthetic liner were to fail, this area would be small compared to the total lined area of the pond and would still be contained by the secondary clay liner. Additionally, we will be installing monitoring wells to check for leaks around the stack.
Q.	What is the process for testing the liner?
A.	There are two different types of testing controls.  The first level of testing comes from the manufacturer and it includes several different types of material testing, for example shear testing for strength and spark testing to detect pinhole leaks.  The other level of control and testing happens in the field.  The liner material is delivered in 20 ft wide rolls that are then fused together using a process similar to welding.  The joints are designed so that they can be pressure tested in the field to ensure there are no leaks.  Sections of the fused joints are also cut out for destructive strength testing in the lab.
Q.	Will the topsoil from the extension area be used to cover the existing stack area?
A.	Topsoil from the extension area will be stored in accordance with Alberta Environment guidelines for future reuse.  This may include use in the final closure of the existing gypsum stack when it reaches its final design elevation.
Q.	Do you reuse the water that is put into your process?
A.	Yes, we do.  It is a closed system designed to maximize water use.  All of the water that is sent to the pond as part of the slurry is returned to the phosphate plant for reuse in the process.  There it is used for cooling, filter cake washing and to slurry the gypsum.
Environmental Assessments
Q.	What are the environmental impacts?
A.	We are evaluating the potential environmental impacts of the extension.  These include groundwater, air quality, aquatic, noise, materials management, soil management, surface water, historical resources and vegetation and wildlife.  The results of these evaluations will form part of our application for an environmental approval from Alberta Environment.
Q.	What about construction noise?
A.	We do not expect much impact from construction noise on our neighbors.  The construction site is not elevated but is at ground level, north of the existing stack which will tend to limit noise.  Further, the existing area vegetation will tend to reduce the level of noise from construction.  We will also be monitoring the level  of noise as construction begins.
Q.	How loud will it be during construction and how late at night will I be able to hear construction noise?
A.	We are sensitive to potential impacts on our neighbors and we will do our best to minimize impacts.  The anticipated construction schedule will be during daylight hours from spring until fall, similar to our current annual gypsum dyke construction schedule.
Q.	Could you improve the appearance of the stack?
A.	While a gypsum stack is active, it is difficult to vegetate the surface due to low pH.  However, last summer we planted several test plots to evaluate the feasibility of vegetation of at least part of the slope.  We have had success at improving the appearance of our inactive gypsum stack at our Fort Saskatchewan facility which has been revegetated for several years.
Q.	What about the radioactivity of the gypsum – is it dangerous?
A.	Some phosphate rock contains Naturally Occurring Radioactive Material (NORM).  The levels of radiation are very low and do not pose a health threat to either our workers or to our neighbors.  The fertilizer manufacturing process does not increase the amount of NORM present.  We use phosphate rock from Agrium’s Kapuskasing mine in Ontario that contains very low NORM levels.  The gypsum produced from this rock contains levels of NORM that are typically found in Canadian rocks and soils making it potentially suited to a broad range of alternative uses.
Q.	Do employees working in the phosphate plant or on the gypsum stack wear radiation badges like the ones x-ray technicians wear?
A.	We monitor employee exposure in a number of different ways.  One way is area monitoring for radiation and another is personal exposure monitoring.  The personal exposure does include the use of radiation badges, although levels are so low that it is not required by Government.
Q.	Has anyone outside of Agrium ever reviewed what you are doing to protect worker health?
A.	We are reporting our monitoring results to Health Canada and Alberta Labor is fully aware and supportive of our programs.  Our safety personnel have participated in the Western Canadian and Federal NORM guideline committees and our approach has been used as a model for radiation control and employee monitoring programs.
Q.	What kind of exposure levels are your workers getting?
A.	The exposures are now and have always been many times below the allowable worker dose.  In fact exposures to our workers are below even the much lower  dose considered safe for the general public.  As a responsible employer, we continue to monitor our workers and actively search for ways to reduce exposure.
Q.	How can I find out more?
A.	Please sign up to be on our mailing list.  We are just beginning our public outreach process.  We will be meeting with interested neighbors, both one on one and in community meetings.  This website was created to keep our neighbours up to date on our project.  In the meantime, if you have any questions call Greg McGlone, General Manager, Redwater & Fort Saskatchewan Fertilizer Operations at (780) 998-6302 or e-mail: gmcglone@agrium.com.