1012 Subsurface Geologic Methods 



space provided for elevation. Entry spaces are also provided for mine 

 level and floor. Supplementary location data is entered in appropriate 

 spaces provided for that purpose along the remainder of the margin of 

 the sheet. 



Sections are indexed in a similar manner to that of plans. Primary 

 indexing is by planar area in which the section is prepared. In addition, 

 however, the exact ordinate value of the line or plane of section is indi- 

 cated. In the space provided the elevation of the top boundary of the 

 section is entered as shown in figure 534c. 



The indexing shown on figure 534c indicates an E-W longitudinal sec- 

 tion of the Smuggler vein with the line of section at 50,023N. It is located 

 in rectangle 505N and 408E; that is, the east and west boundaries of the 

 section are 40,400E and 40,800E, respectively. 



If the section is oblique to the ordinate lines, the line of section is 

 not expressible as an ordinate value; and other means must, therefore, be 

 devised to indicate exact position. Position is indicated by the coordinate 

 value of a vertical line on the section as shown in figure 534d. 



The indexing of oflBce maps and sections is the same as for letter-size 

 data sheets and reports, except that the index entry spaces are in the 

 lower right-hand margin corner of the sheet. 



Filing — The basic filing system is in accordance with the unit-rectangle 

 index value. The primary filing is in order of increasing sequence of 

 provincial or regional east- and north-ordinate index value. Secondary 

 filing is in order of increasing local east- and north-ordinate index value. 

 Within each unit rectangle classification, the data are further sub-filed 

 in accordance with the orientation of plane of the representation — plan, 

 horizontal or composite projection, vertical or longitudinal projection, 

 N— S ordinate section, E-W ordinate section, and diagonal section. The 

 final plan filing is in order of decreasing elevation. Sectional data is 

 filed in order of decreasing elevation of unit-section grid areas, and then 

 in increasing north- or east-ordinate value of the sectional planes. Assay, 

 metallization, geochemical, biochemical, and vegetation data sheets are 

 filed as superimposed overlays on the corresponding geological data sheet 

 or map. The system is essentially the same for the letter-size note and 

 data sheets and office maps. 



In order that the filing system will be practical and efficient, the 

 various filing units are separated by index-tabbed Manila sheets. The 

 more detailed filing subdivisions (such as local-unit-area note and data 

 sheets) are placed in index-tabbed Manila file folders. Subsidiary filing 

 divisions of data contained in the folders are further separated by index- 

 tabbed sheets. The system of tab indexing is described below. 



Letter-size field and data sheets are filed together in steel drawer 

 filing cases. It is desirable that the cases are fire-proofed and if possible 

 located in a fire-proof vault. In the event of loss, usually less than 30 



