§ 1828. PUBLIC INSTITUTIONS TO USE.] The various state institutions, county buildings and public school houses in this state shall use for fuel, North Dakota native or lignite coal, or lignite coal products, North Dakota native natural oil or North Dakota native natural gas, and it shall be unlawful for any officer to purchase for use in such institutions, county buildings and public schools any coal other than that taken from the mines or wells within the boundaries of this State. This section shall not be construed, however, as prohibiting the use of other coal or wood, North Dakota natural oil or natural gas, at such institutions, county buildings and public schools when such other coal or wood or North Dakota natural oil or North Dakota natural gas can be obtained at a cost less than such North Dakota native fuel products, or the use of coal other than North Dakota native lignite coal lignite coal products, North Dakota native natural oil or native natural gas, at such public schools as are located six miles or more from any mine or railroad station within the boundaries of this state; provided, that the comparative cost of such fuel is not greater than that of lignite coal, lignite coal products, North Dakota native natural oil or native natural gas.
All purchases of lignite coal, or lignite coal products, or North Dakota native natural gas native natural oil, shall be based upon proposals published in some newspaper, published in and having a general circulation in the State of North Dakota, and copies of said proposals shall be filed in the office of the Secretary of State at Bismarck, North Dakota on or about the date thereof, and said purchases of such products shall be made from the lowest responsible bidder, and shall be based on the following standard contract grade:
Two thousand (2000) pounds shall constitute one (1) ton standard contract grade of lignite coal.
Standard contract grade of lignite coal shall contain as delivered 33% of moisture, as determined at one hundred five (105) degrees centigrade (c). For actual weight of moisture above thirty-five per cent, deduct proportionately the price per ton.
Standard contract grade lignite coal, water-free basis, shall contain from ten (10) to fifteen (15) per cent of ash. For each one (1) per cent of ash above fifteen (15) per cent deduct two and one quarter (274) per cent of the bid price per ton. For the one (1) per cent below the ten (10) per cent, add one and three-fifths (185) per cent of the bid price per ton.
Standard contract grade lignite coal shall contain, water-free basis, not over two (2) per cent of sulphur. For each one (1) per cent, or major fraction thereof above two (2) per cent, deduct two (2) per cent of the bid price per ton.
Standard contract grade lignite coal shall contain, water-free basis, nine thousand five hundred (9,500) British thermal units (B. T. U.) and the price per ton shall be based upon that number of heat units. When the British thermal units (B. T. U.) are in
