2017: C1 cash costs $1.43 per pound
2018: C1 cash costs $1.93 per pound
2019: C1 cash costs $2.06 per pound:
C1 cash costs $2.21 for Q1 2019, $2.01 for Q2 2019, $2.05 for Q3 2019, and $2.01 for Q4 2019

Besides lower copper price, significant rising in C1 cash costs was the other main reason for poor financial performance and thus TKO share price.

GAAP breakeven copper price:

TKO 2019 adjusted net loss was $68.61 millions Cdn or $58.78 millions USD.  TKO produced 125.9 million pounds of copper 2019  The average price of LME copper price was $2.72 USD per pound for 2019.  The GAAP breakeven copper price based on the above data would be $3.19 USD per pound, very close to my estimate of $3.2 USD per pound that I had posted on this board previously.