Mining and Metallurgy Volume 66

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...lower half of the circle when the actual widths of ore are known, and when it is necessary to make up the figures of probable ore, as at the time of making annual or semi-annual reports, red figures are written in the upper half of the circle to represent the probable thickness of the ore; and later on, when the development warrants it, the black figures are inserted underneath. The same color-scheme may be used for ore actually developed and probable ore, red Consulting Engineer. Fig. 1.--Ideal Longitudinal Elevation Of A Mine. figures representing the probable ore being first inserted in the column headed "Developed," and when the ore is developed the black figures should be inserted in the time-space when the development was completed. There should be an ore-reserve sheet for each year, and the space between the levels divided into four spaces if quarterly estimates are made, as shown on the 130-ft. level, or into 12 spaces if the figures are worked up monthly, as shown on the 230-ft. level. Then there should be a sheet kept to enter the ore developed and extracted each year, 10 spaces being a con Fig. 2.--Ore-reserve Sheet To Accompany Elevation, Fig. 1. venient number, thereby covering 10 years, so that the record of the development and extraction by years can be seen at a glance. In mines where the value of the ore is kept it is convenient to insert in one lower quarter of the circles the width of the ore, and in the second lower quarter the value of the ore. The idea can be carried a little further by using squares instead of circles at the corners, in which the widths and values are written, and making a circle in the center of each large block in which to insert the average value of the block of ore. As it is always well to have the figur...