Section 18
SEC. 18. Chapter two of Act Numbered Twenty-three hun-di'ed and thirty-nine is hereby amended by adding at the end thereof the following article: "ARTICLE X.-Ad valorem tax on output of mines. "SEC. 100a. Rate and basis of tax on mines.-There shall be levied.and collected on the gross output of each mine an ad valorem tax equal to one and one-half per -cent of the actual market value of such output. This tax shall not be imposed with respect to valid perfected mining concessions granted prior to April eleventh, eighteen hundred and ninety-nine, until the year nineteen hundred and eighteen. "SEC. 100b. Time and manner of collection.-All ad valorem taxes on the value of the output of mines shall be assessed and paid before the removal of any such output from the locality where it is mined. But the output of mines may be removed from such locality without the payment of the tax herein imposed, if the owner or concessionaire of the mine shall first file a bond with the Bureau of Internal Revenue in the form and amount and with such sureties as the Collector of Internal Revenue may require, conditioned upon the future payment of said tax at such is of tax. time and place as the Collector may direct. For the purpose of establishing a uniform basis for the assessment of this tax the Collector of Internal Revenue shall, upon the taking effect of this article, and from time to time thereafter, make an assessment of the actual market value of the various products of the mines in the Philippine Islands subject to the tax herein imposed. Such assessment shall be made from the most reliable data available and shall be published in the Official Gazette for the information of the taxpayers."