Abandoned Cassidy Lake Potash Mine - an Earthcache EarthCache
Abandoned Cassidy Lake Potash Mine - an Earthcache
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Potash was discovered in large quantities in the southeast area of New Brunswick, the deposit being the second largest in the world after an area in Saskatchewan.
The History of Potash in New Brunswick
The element potassium (K) is essential to plant and animal life. Without potassium leaves will wither, muscles grow weak and the nervous system convulses. Potash is marketed primarily as fertilizer. Small quantities are also sold to the pulp and paper industry and to makers of soaps, detergents, glass, drugs and furnace fluxes.
A primary source of potassium is the mineral sylvite (KCl) which often occurs as an intergrowth with another mineral halite (salt, or NaCl). The mixture is known as potash or sylvinite. The higher the mixture of sylvinite content, the higher the grade of potash ore.
Potash was formed during the Mississippian age. During that time much of what is now southeast New Brunswick possessed a hot and arid climate and lay beneath an extensive shallow sea. The seawater slowly evaporated over time, causing potassium and other salts to precipitate from the brine, much like a salt solution is left on a plate when the liquid dries. After the ocean receded thick layers of other sediments buried the potash and related deposits where they remained undisturbed for 325 million years.
Salt deposits were first discovered in the Sussex area in the early 1800’s when area residents tapped local salt springs, dried the brine to produce halite which they used in food preservation. In 1971 government geologists drilled two holes east of Sussex hoping to discover commercial salt deposits. They discovered salt, and thick beds of potash. Potash was discovered in large quantities in the area surrounding Sussex, with the deposit being the second largest in the world after an area in Saskatchewan. Two mines were built near the town, one in Penobsquis, 8 km. east, and another at Cassidy Lake, 10 km. southeast. CN Rail built trackage to serve both mines, which employed hundreds from the surrounding area.
In the 1900’s New Brunswick had two world-class potash mining and processing facilities, namely The Potash Corporation of Saskatchewan Inc.’s New Brunswick Division and Cassidy Lake Division. Until recently the Cassidy Lake Division mined and provided the company with custom and selected value-added processing. The New Brunswick Division at Penobsquis functions as an integrated mine/mill facility. In 2002 exploratory drilling southeast of the mine has resulted in the discovery of additional and potentially significant potash reserves. The expansion is expected to more than double the annual potash production.
Potash is mined underground at a depth of between 400 to 700 meters. Machines known as roadheaders are used to remove potash ore underground. These huge mining machines have a rotary cutting head mounted on a boom and can excavate 300 to 500 tonnes of potash ore per hour. They crawl forward along a working face slowly swinging the boom up and down and back and forth. The machine excavates potash ore in the front and gathers it onto a conveyor belt at the rear. PCS mills its ore into four commercial grades: granular, coarse, standard and fine. The processed potash is loaded onto railcars and carried by train to storage facilities in Saint John. From there it is shipped to Western Europe, the United Sates, Central and South America, Asia and Oceania. Rock salt is also mined and is used for road salt. Approximately half of the production stays in New Brunswick while the rest is shipped through the US northeast.
Typically, underground potash deposits are overlain by water bearing formations that pose considerable threat to the ongoing operation of potash mines. There have been a number of potash mine floods over the past 30 years, including New Brunswick. Beginning about 1997 the Sussex potash mine began experiencing a brine inflow problem that has increased every year, peaking last year at about 1,800 GPM (US gallons per minute). Grouting efforts into the inflow zone, along with sustained drilling and grouting efforts underground, have sealed at least some of the flow paths and have helped to stem the flow of brine into the mine but at this time the source of the water has not been determined.
The Cassidy Lake Division
Potash was mined to the south east of Cassidy Lake, the mine was opened by Dennison and was later purchased by the Potash Company of Canada Limited’s Potacan Mining Co. property. In the late 1900’s areas of the mine began to flood, shortly after it was allowed to flood completely and production was terminated. In 1998 Potash Corporation of Saskatchewan Inc. purchased the properties in New Brunswick – a flooded mine and a functioning mill. The flooded mine was renamed Cassidy Lake Division of PCS. At the time of closure the annual capacity of the mine was 1.3 million tonnes. Today the mine acts as water storage for its sister operation in Penobsquis. Currently a small group of employees manage the company’s brine pipeline to the Bay of Fundy. Approximately 300 – 350 tanker trucks haul brine from the Sussex mine daily. Most of these tanker trucks haul the brine to the Cassidy Lake Division. The brine hauled to Cassidy Lake is a slurry of potash in brine. The slurry is deposited into holding lagoons where the brine is taken off and pumped via the brine pipeline to be deposited into the Bay of Fundy in the area of Giffin’s Pond just south of St. Martin’s. The remaining tanker trucks haul brine to the company’s potash terminal in Saint John for disposal into the Bay. The community continues to be concerned about the transport of brine from the New Brunswick production site to the Cassidy Lake site for disposal, especially with truck safety and speed and the company is addressing these concerns.
Recently a 30-km brine pipeline was built to ship excess brine from the Penobsquis mine site to the company’s brine pond at Cassidy Lake and into the Bay of Fundy. This has lowered the daily volume of brine hauled away to less than half the 2008 volume. In 2015 the Cassidy Lake mine building was demolished. In 2016 the Potash Mines in Penobsquis were closed as well, effectively bringing potash mining in New Brunswick to a halt
The posted coordinates will take you to the visitors parking area at the Cassidy Lake mine. To log this earthcache send an email to us through our profile with the answers to the following questions:
1. What is the importance of potash?
2. What is the primary element that is found in potash and what is it’s chemical symbol?
You must answer the questions or your log will be deleted. In your log please take the time to describe what you find interesting about the Cassidy Lake mine. And remember, do not answer the questions in your log!
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