Gypsum Resources Australia (GRA) celebrated a century of mining operations at the Kevin Mine near Penong on Monday.
More than 80 people were in attendance for a ceremony and tour of the mine site close to Lake MacDonnell, including current and past employees of GRA, Boral, CSR and Waratah, Federal Member for Grey Rowan Ramsey, Member for Flinders Peter Treloar and Ceduna mayor Perry Will.
GRA general manager Alistair Kelsh said it was a thrill to be celebrating 100 years of operations and was looking forward to many more.
"It is a unique circumstance for a mine to have existed for 100 years which is testament to the quality of the resource and people here at GRA's Ceduna operations," he said.
"GRA's gypsum mining operation is a vital component of the Australian and New Zealand construction industry providing raw material to a majority of the plasterboard and cement plants on Australia's east coast and New Zealand.
"GRA intends to continue mining here at the Kevin Mine well into the future with more than 100 years of resource still remaining."
Mr Treloar praised the efforts of GRA's mining operation at Kevin.
"Congratulation to the GRA gypsum mine on the celebration of a century of mining at Lake MacDonnell," he said.
"For one hundred years the mine has contributed to the local, regional and national economy."
During the ceremony Mr Kelsh spoke about key events during the 100 years of gypsum mining operations at the site.
Mining operations commenced in 1919, and until 1923 gypsum output was bagged and carted by bullock wagon about eight kilometres to Point Sinclair.
William Sleep, whose farm adjoined the deposits, initially conducted operations and his 12 children helped with the bagging and carting.
The loaded gypsum was bound for Sydney, with an output of 7203 tonnes in 1920.
Construction of the Penong-Wandana railway line in 1924 meant gypsum was carted to Penong and then transferred to Thevenard, with an output of about 30,000 tonnes per year by the end of the decade.
Operations took a hit at the start of the 1930s thanks to the Great Depression and slowed down until 1947, with about 17,000 tonnes per annum carted by 1950.
The mine continued to grow throughout the 1950s and in 1966 a direct rail line from Kevin to Thevenard was opened which helped increase output to 278,000 tonnes by 1970.
Output passed one million tonnes for the first time in 1986 and in 2018 that had grown to 2,200,000 million tonnes.
Mr Kelsh also acknowledged the contribution of past and present employees, making special note of long-term employees Lee Warmington after 44 years of service and Malcolm 'Spuddy' Shipard for 38 years.
A plaque was unveiled by chairperson of the GRA board of directors Andrea Pidcock, Mr Ramsey and Mr Treloar.
Ms Pidcock then spoke about the company's ongoing commitment to the gypsum mining operation.
She said its importance to the construction industry was highlighted in 2017 by the unplanned Port of Thevenard outage and she expressed appreciation for the quality of current operations.
Lunch provided by the Penong School Parents and Friends group and site tours followed the ceremony.