The news comes as a result of the decision to slow down operations at Woodsmith Mine to "buy some time" to find alternative funding options.
The company has only got six months until its current cash resources run out and needs to find a way to fund the next phase of construction.
A spokesperson from the company said: "We are sorry to see some of our colleagues leave this week, as part of the slowdown which we announced on Tuesday. Yesterday we took the sensible decision to wind back a number of the night shifts on some of our sites, which will preserve activity for longer.
"We are doing our utmost to find a solution to the funding situation we are currently in and to ensure the project is in the best possible position to ramp back up to full speed as and when that happens.
Scarborough officially smashes temperature record as Met Office confirms new hottest day
Whitby Regatta 2022: Red Arrows unable to display over town as sea fret rolls in
RNLI issue weever fish warning for Yorkshire coast
Post-war asbestos bungalows to be demolished in Scarborough as plans for new terraced homes approved
Yorkshire Water announces first hosepipe ban for more than 27 years – with fines of up to £1,000
"We are as committed to building this project today as we were on day one and we are exploring all options, whilst also trying to minimise the impact on the whole team."
Scarborough Council leader, Cllr Steve Siddons wrote to PM Boris Johnson earlier this week requesting a meeting to discuss Sirius' situation.
Cllr Siddons thinks the Government should intervene to provide financial assistance, something both Boris Johnson and Theresa May declined to do.
MP Robert Goodwill, who pledged to support Sirius "every step of the way", said he already met with the PM on September 2 but added that a new meeting in Scarborough could be "useful".
However, he thinks the best option at the moment is for Sirius to find a company "with expertise and capital" to partner up with them.