		Decommis- sioning, restoration and similar liabilities			Deferred share units (note 24a)			Restricted share units¹(note 24a)			Performan- ce share units (note 24a)		Other			Total
Balance, January 1, 2020	$	302,116		$	3,876		$	5,477		$	—	$	2,956		$	314,425
Net additional provisions made		5,868			1,628			3,642			1,257		15			12,410
Amounts used		(18,737	)		(497	)		(2,646	)		—		(1,824	)		(23,704	)
Unwinding of discount (note 6g)		3,543			—			—			—		—			3,543
Effect of change in discount rate		43,180			—			—			—		—			43,180
Effect of foreign exchange		7,162			191			116			43		(3	)		7,509
Effect of change in share price		—			3,521			3,860			730		—			8,111
Balance, December 31, 2020	$	343,132		$	8,719		$	10,449		$	2,030	$	1,144		$	365,474

¹Certain amounts relating to the Arizona segment are capitalized.

Provisions are reflected in the consolidated balance sheets as follows:

December 31, 2020

Decommis-sioning, restoration and similar liabilities

Deferred share units (note 24a)

Restricted share units¹ (note 24a)

Performance share units (note 24a)

Other

Total

Current (note 14)

20,308

8,719

4,648

—

33,675

Non-current

322,824

—

5,801

2,030

1,144

331,799

343,132

8,719

10,449

2,030

1,144

365,474

		Decommis-sioning, restoration and similar liabilities			Deferred share units (note 24a)			Restricted share units¹ (note 24a)			Performance share units (note 24a)		Other			Total
Balance, January 1, 2019	$	202,024		$	4,288		$	12,201		$	—	$	411		$	218,924
Net additional provisions made		68,881			1,479			2,885			—		2,882			76,127
Amounts used		(4,136	)		(1,668	)		(9,380	)		—		(341	)		(15,525	)
Unwinding of discount (note 6g)		4,392			—			—			—		—			4,392
Effect of change in discount rate		23,635			—			—			—		—			23,635
Effect of foreign exchange		7,320			99			225			—		4			7,648
Effect of change in share price		—			(322	)		(454	)		—		—			(776	)
Balance, December 31, 2019	$	302,116		$	3,876		$	5,477		$	—	$	2,956		$	314,425

¹Certain amounts relating to the Arizona segment are capitalized.

December 31, 2019		Decommis- sioning, restoration and similar liabilities		Deferred share units (note 24a)		Restricted share units1 (note 24a)		Performan- ce share units (note 24a)		Other		Total
Current (note 14)	$	23,621	$	3,876	$	4,468	$	—	$	1,610	$	33,575
Non-current		278,495		—		1,009		—		1,346		280,850
	$	302,116	$	3,876	$	5,477	$	—	$	2,956	$	314,425

Decommissioning, restoration and similar liabilities are remeasured at each reporting date to reflect changes in discount rates, which can significantly affect the liabilities.

Decommissioning, restoration and similar liabilities

Hudbay's decommissioning, restoration and similar liabilities relate to the rehabilitation and closure of currently operating mines and metallurgical plants, development-phase properties and closed properties. The amount of the provision has been recorded based on estimates and assumptions that management believes are reasonable; however, actual decommissioning and restoration costs may differ from expectations.

During the year ended December 31, 2020, additional provisions were recognized mostly as a result of lower discount rates and increased cost in Peru and Manitoba as well as additional disturbance in Peru.

During 2019, additional provisions were recognized as a result of higher estimates for closure activities of tailings facilities at the Manitoba operations to ensure compliance with higher industry-wide standards for tailings management safety and, to a lesser extent, increased mine activity footprints and the resulting higher disturbance at the Constancia operation.

Hudbay's decommissioning and restoration liabilities relate mainly to its Manitoba operations. Management anticipates that the assets in Flin Flon will be placed on care and maintenance once mining activities are completed at 777 mine in order to maintain optionality for restart should a new mine be found in the Flin Flon area. The majority of closure activities will occur once all mining activities in Manitoba are completed. These provisions also reflect estimated post-closure cash flows that extend to the year 2100 for ongoing monitoring and water treatment requirements. Management anticipates most decommissioning and restoration activities for the Constancia operation will occur from 2035 to 2070, which include ongoing monitoring and water treatment requirements.

These estimates have been discounted to their present value at rates ranging from 0.12% to 1.65% per annum (2019 - 1.59% to 2.39%), using pre-tax risk-free interest rates that reflect the estimated maturity of each specific liability.