1010 Subsurface Geologic Methods 



classification of the reserve on the basis of ecojiomic profitability and 

 availability. The infolded right-hand portion of the sheet contains tabula- 

 tion headings for production or depletion data to be entered when an 

 ore-reserve block is mined. In the upper right- and left-hand corners of 

 the sheet are entry spaces for coordinate indexing to indicate the location 

 of listed blocks within a 400' x 500' unit rectangle area (fig. 533). 



Three-Dimensional Representation Sheets — Blank 23''x 42" oflBce-map 

 size sheets are used. The representation is oriented with the vertical axis 

 parallel to the long dimension of the sheet. The plan area covered by each 

 block diagram is 8"x 10" note-sheet size. 



Reports — Reports are on standard 8^" x IV note-size paper. A place 

 for coordinate indexing by rectangle-grid area is provided in the upper 

 right-hand corner of the cover page as indicated in figure 535d. 



Along the binding edge of the report cover, name, ownership, and 

 location data are entered as on the note sheets. This data, readily visible, 

 facilitates accessibility of reports. 



Indexing and Filing 



Efficient filing is one of the basic considerations leading to the de- 

 velopment of the mapping system described in this discussion. Without 

 efficiency in filing, all other merits of a mapping system are to a large 

 extent neutralized. Geologic and assay data should be filed so that it is 

 readily located. 



At some mining properties there are thousands of geologic note sheets 

 and hundreds of maps to which one must constantly refer. Such data are 

 filed more or less haphazardly by mine and by level. With the system of 

 mapping used at these properties, it is impossible to file data efficiently 

 and systematically. Often an abundance of data is not properly utilized, 

 for no one has the time to search for it. Consequently, much time and 

 energy is wasted in remapping geology because the geologist is not aware 

 of available long-buried information in the files. Poor filing alone con- 

 tributes more to poor utilization of geological personnel than any other 

 factor. 



The following filing system is possible because a critical combination 

 of map scales, note-sheet size, office-map size, coordinate values, and map- 

 grid layout have been determined. The indexing and filing is based on 

 the previously described note-sheet and office-map grid system. 



Indexing — Note Sheets, Assay Record Sheets, Survey Sheets, Ore Re- 

 serve Sheets, Reports — A printed entry space is provided in the upper 

 right-hand corner of the letter-size note and data sheets for coordinate and 

 elevation indexing. It will be recalled that the map-grid system is inte- 

 grated with the coordinate values in a manner that the ordinate values of 

 the boundaries of note-sheet and map areas are even multiples of 400 or 

 500. This fact permits dropping the last two digits of the local ordinate 

 value in indexing; thus, if the local ordinate value of the north boundary 



