delivered the Opinion of the Court.
*139In this cause, the relator, H. Evan Roberts, filed a petition to enjoin the respondents, the State Board of Equalization of the State of Montana, the members of said Board, Ravalli County, Montana, the County Assessor and the County Treasurer of Ravalli County, from assessing the net proceeds of the relator’s mining operations for the year 1959 by combining the calculated net proceeds of said mining operations of 1958 with the net proceeds of said mining operations of 1959 and then dividing by two. This court determined that it was proper for it to take original jurisdiction in this cause, and issued an order to show cause directing the respondents to appear before the court on September 7, 1960, and show cause why they should not be permanently enjoined and restrained from assessing relator’s net proceeds for the year 1959 in an amount of more than $298,426.70 or from collecting or attempting to collect any net proceeds taxes from relator based upon an assessment in excess of $298,426.70.
The facts of this ease are not in issue. Briefly, they can be stated as follows:
By section 1 of Chapter 181, Montana Session Laws of 1959 (approved March 7, 1959), the State Legislature amended section 84-5408, R.C.M.1947, relating to the taxation of net proceeds of mining property. Insofar as important in the consideration of the instant case, the amended law reads:
“On or before the first day of July in each year the state board of equalization shall transmit to the county assessor of each county in which such mines and mining claims are situated, the valuation of the net proceeds of such mines and mining claims for the purpose of taxation, as the same have been determined and fixed by such state board of equalization. The said valuation for the purpose of taxation shall he an amount equal to the average net proceeds from such mime for the five calendar years next preceding, or for as many years next preceding as the mine has produced gross yield, or for as many years nexl preceding as this act has been in effect, whichever is less. The *140average net proceeds for valuation shall be computed by dividing the total net proceeds for such period by the number of years for which such net proceeds were taken into account. In determining net proceeds of each individual year for averaging to determine valuation for purposes .of taxation, the actual annual net proceeds as defined in section 84-5403 of the Revised Codes of Montana, 1947, including losses, if any, from such mines and mining claims shall be taken for each year rather than? the average valuation for such year. '* * *” (The new matter which was added by the amendment is italicized.)
This cause arises out of the above-quoted section, as amended. The relator operates a fluorspar mine in Ravalli County, and so operated in the calendar year 1958 that in 1959 there was assessed on the 1958 production net proceeds of $1,057,695.88. The tax on this assessment was paid. In the calendar year 1959 the net proceeds of realtor’s operation, calculated by the State Board of Equalization under section 84-5403, as amended, was the sum of $298,426.70. Over the protest of the relator, the State Board of Equalization assessed the 1959 net proceeds at $678,061.30, and forwarded this assessment to the County Assessor of Ravalli County. This assessment was calculated by taking the net proceeds for 1958 of $1,057,695.88 and adding the net proceeds for 1959 of $298,426.70 and dividing the result by two in attempted compliance with section 84-5408, as amended.
The relator contends that the attempt to assess his net proceeds in the amount of $678,061.30 is invalid because section 84-5408, as amended, is unconstitutional in that it violates Article XII, §§ 1, 3, and 11, of the Montana Constitution.
Article XII, § 3, of the Montana Constitution provides:
‘ ‘ * * * and the aovnual net proceeds of all mines and mining claims shall be taxed as provided by law.” Emphasis supplied.
Relator argues that a tax on an average of annual net proceeds, as provided by the statute in question, is not a tax on *141“annual net proceeds” and therefore not within the purview of this constitutional provision. We conclude that this argument has merit.
It can be demonstrated that taxes levied on the basis of averages will not produce the same amount of money as taxes levied on “annual net proceeds”. Let us assume that the production of a mine results in actual annual net proceeds as follows, and determine what the average annual net proceeds will be under the same circumstances:
Actual Average
1959 $10,000 $10,000
1960 5,000 7,500
1961 6,000 7,000
1962 7,000 7,000
1963 8,000 7,200
Total Assessed Values $36,000 $38,700
Thus, over a five-year period the revenue produced on annual net proceeds is based upon an assessment of $36,000 while an average of the annual net proceeds for as many years produces revenue on the basis of an assessment of $38,700. The extent to which the law departs from annual net proceeds is even more graphically illustrated if we take the same total production for five years, but put the year of heavy production last. Thus, if the year of heavy production is in 1963, the picture is this:
Actual Average
1959 $ 5,000 $ 5,000
1960 6,000 5,500
1961 7,000 6,000
1962 8,000 6,500
1963 10,000 7,200
Total Assessed Values $36,000 $30,200
*142If we take into account losses, for which section 84-5408, as amended, provides, the law can be demonstrated to depart even more from a tax on “annual net proceeds” as follows:
Net Proceeds Actual Average
1959 —$10,000 .......... ............
1960 + 5,000 5,000 ...
1961 -f 6,000 6,000 333.33
1962 4- 7,000 7,000 2,000.00
1963 + 8,000 8,000 3,200.00
Total Assessed Values $26,000 $5,533.33
Since the law permits consideration of losses it can be seen that there could be a loss of revenue to the state and there will be an even greater departure from “annual net proceeds”.
We conclude that this average of annual net proceeds, as provided by section 84-5408, as amended, is not the same as the “annual net proceeds” provided in Article XII, § 3, of the Montana Constitution and therefore that the law is unconstitutional.
Because of our conclusion, the other constitutional questions need not be considered.
Relator also contends that section 84-5408, as amended, was misconstrued by the respondents in that they took into consideration the annual net proceeds for the year 1958, in determining the amount of the relator’s tax for the year 1959 and the statute was approved on March 7, 1959. Because of the disposition of this cause on the constitutional question involved, we find it unnecessary to consider this additional ground urged by the relator.
For the above-stated reason it is ordered that the respondents be permanently enjoined and restrained from assessing relator’s net proceeds for the year 1959 in an amount of more than $298,-426.70 or from collecting or attempting to collect any net proceeds taxes from relator based upon an assessment in excess of $298,426.70 for that year.
*143MR. CHIEF JUSTICE HARRISON, MR. JUSTICE ANGSTMAN and THE HONORABLE VICTOR H. FALL, District Judge, sitting for MR. JUSTICE BOTTOMLY, concur.