NOTES RECEIVABLE AND ADVANCES, NET
 3 Months Ended
Mar. 31, 2022
Receivables [Abstract]  
NOTES RECEIVABLE AND ADVANCES, NET NOTES RECEIVABLE AND ADVANCES, NET
Notes receivable and advances, net at December 31, 2021 and 2020 include:
December 31, 2021December 31, 2020
Current portion
Tonogold note receivable, face value$— $4,475,000 
Unrealized gain— 1,023,500 
Tonogold note receivable, fair value— 5,498,500 
Sierra Springs advances receivable 4,935,000 1,650,000 
  Other notes receivable29,545 — 
Total notes receivable and advances, current portion$4,964,545 $7,148,500 
Non-current portion
Tonogold note receivable, face value6,650,000 — 
Unrealized gain605,000 — 
Tonogold note receivable, fair value7,255,000 — 
MCU-P note receivable, face value2,000,000 1,180,000 
Unamortized discount for implied interest
(401,159)(319,060)
MCU-Philippines note receivable, non-current portion, net8,853,841 860,940 
Total notes receivable and advances, net$13,818,386 $8,009,440 
We expect the Tonogold Note to be cancelled in exchange for the membership interests of Comstock Mining LLC (see Note 22, Subsequent Events), which investment is classified as a non-current asset at December 31, 2021.
NOTES RECEIVABLE AND ADVANCES, NET
Notes receivable and advances, net at March 31, 2022 and December 31, 2021 include:
March 31, 2022December 31, 2021
Current portion
Sierra Springs advances receivable $4,935,000 $4,935,000 
Other notes receivable27,043 29,545 
Total notes receivable and advances, current portion$4,962,043 $4,964,545 
Non-current portion
Tonogold note receivable, face value— 6,650,000 
Unrealized gain— 605,000 
Tonogold note receivable, fair value— 7,255,000 
MCU-P note receivable, face value— 2,000,000 
Unamortized discount for implied interest
— (401,159)
MCU-Philippines note receivable, non-current portion, net— 1,598,841 
Total notes receivable and advances, net$4,962,043 $13,818,386 
Tonogold Option Agreement, Reconveyance of Lucerne mine and related assets, and Tonogold Note Receivable
We recognized a loss on the change in fair value of $605,000 and a gain of $745,500 in other income and expense for the three months ended March 31, 2022 and 2021, respectively. On March 31, 2022, we agreed to extinguish the Tonogold note receivable principal of $6,650,000 in exchange for the membership interests of Comstock Mining LLC under the Option Agreement (see Note 2, Acquisitions and Investments).
Advances to Sierra Springs Opportunity Fund, Inc.
On January 3, 2022, the Company made an additional SSOF Advance of $1,300,000, for use by SSE in paying deposits for contracted property purchases. This amount was fully repaid on January 26, 2022. SSE assigned all
assignable rights, title and interest in SSE’s property purchases to the Company until such time as the SSOF Advances are repaid.