1030 Subsurface Geologic Methods 



tion on mining geology maps. The colors used should be dull (olive greens, 

 gray-blue, and brown) and superimposed very lightly. 



Assay, Metallization, and Ore Reserves — Assay-metallization data are 

 represented to facilitate integration with geologic data. Compositional 

 values are represented by a progressive chromatic series, (fig. 542) Black 

 represents "barren" vein or waste. Colors used are chosen for each par- 

 ticular area or deposit. If copper is the chief economic metal present, 

 copper percentages are indicated by color progression from yellow to red 

 (inclusive). A color break is made for a 1% grade variation. Copper 

 content is indicated, thus: minus 1%, black; l%-2%, yellow; 2%-3%, 

 orange; 2>%-A%, brick-red; 4%-5%, red; and 5% plus, scarlet. Sim- 

 ilarly, lead and zinc content may be indicated by blue-red (purple) and 

 yellow-blue (green) color progressions, respectively. The "stronger" or 

 more brilliant color is added with increasing grade of ore, and the result- 

 ant chromatic progression is quantitatively cumulative. 



Assay filing-sheet records are posted on letter-size, tracing-paper, 

 overlay sheets which are stapled superimposed on the geologic note 

 sheets; cut-sample assay values are posted in colored inks. If only two 

 or three economic metals are present, the assay is posted adjacent to the 

 point where the sample was taken. If veins are closely spaced, or if ore 

 is complex, a number (in color to indicate approximate ore-grade classi- 

 fication) is posted at the sample point; width and grades are numerically 

 indicated on an attached listing sheet. Car samples are represented on the 

 excavated area by appropriate grade-color pencil shading or hatching. 



Assay office-map representation is posted directly on the geological 

 maps if the veins are not too closely spaced. Assays are indicated in the 

 same manner as side notes. A narrow side-note line (east-west or north- 

 south) is posted (with a ruling pen and straightedge) from the point where 

 the sample was taken to 2" from the edge of the excavation; sample data 

 for each location are posted on the outward projection of side-note line; 

 all figures for any one metal will be in a column, usually curved to con- 

 form with the mine-excavation trend. The columnar position indicates the 

 metal given (fig. 543). 



Sample data are indicated in the following assay order: width, ounces 

 gold, silver, percent copper, lead, zinc, etc. If grades for certain metals 

 are missing, a dash line is substituted for the value. 



Wd. Au Cu Pb Zn 



3.1' 0.09 .... 4.2 8.9 



4.2' 0.15 3.1 8.3 7.2 



2.6' 0.17 4.1 .... 9.9 



Metal-grade values are posted in colors conforming to grade (indi- 

 cated in the legend chart). The predominant economic metal is posted 

 in yellow-red chromatic progression. Minor accessory metals are indi- 

 cated by black. 



Metallization maps are prepared on clear, plastic, overlay sheets. 



