Glossary

The terms used in Strip Logs and this manual, as the app uses them. The Student guide shows them at work on the demo data.

Alpha (α): For oriented core: the acute angle between a structure’s plane and the core axis, 0 to 90 degrees. 90 is straight across the core, 0 runs along it. On the log, each structure line is drawn at its alpha.
Assay: A laboratory’s result for one element in one sample, such as Au in ppm. A sample can have several assays for the same element: repeats, other methods, batches that failed QC. The log shows one per sample.
Assay rank: The site’s preference between methods for the same element (ASSAY_RANK): the lowest is preferred. Where a sample has results from several methods, the log shows the preferred one.
Azimuth: A compass direction, 0 to 360 degrees clockwise from north. A hole’s azimuth is the direction it points, measured on the same grid as its collar.
Back-bearing: The direction exactly opposite a bearing: the azimuth plus or minus 180 degrees. Data health flags a stored survey azimuth that is the back-bearing of the logged one, because the hole would then point the wrong way.
Below detection: A result smaller than the laboratory can measure, reported as, say, “<0.01” and marked < in the database. By default the app counts it at half its stored value, normally the detection limit; Rules on the Log tab can use it as written.
Beta (β): For oriented core: the angle round the core from the orientation reference line to the structure, 0 to 360 degrees. On the log, a structure line leans left when beta is between 0 and 180 degrees and right otherwise.
Blank: Material with almost none of an element, sent to the laboratory with the samples. A blank that reads high points to contamination. Data health counts the blanks in the QC sheet.
Category and attribute: How the database groups logged fields. A category (Lithology, Alteration, Structure …) holds attributes, the fields themselves (Lith1, AltInt1, Alpha …). Each attribute can be a column on the log.
Collar: The point where a drillhole starts: its east, north and RL (elevation) on a grid, and the hole’s total depth. The header above the log gives them.
Coordinate set: One set of collar coordinates for a hole: planned or surveyed, or on another grid. Report coordinates under Print adds a second set to the header, the PDF and the intercept table.
Cut-off: The lowest grade that counts as mineralised when finding intercepts. A sample at or above it starts or extends an intercept.
Data health: The checks the app runs on every workbook it loads. Each finding says what is odd, why it matters and what to do; nothing in the data is changed.
Depth (downhole): Distance along the hole from the collar, in metres. Every column of the log shares one depth axis. It is not the vertical depth below surface unless the hole is vertical.
Detection limit: The smallest value a method can measure reliably (LOWERDETECTION). Results below it are reported as below detection.
Dilution (internal): Samples below the cut-off kept inside an intercept, between richer samples. Max dilution is the longest run of them allowed, in metres. They count at their own grade, so dilution lowers the intercept’s average.
Dip: How steeply a hole points down from horizontal, 0 to 90 degrees. Sites differ in sign: many record downward as negative (-60), and Data health says which convention it found.
Downhole width: An intercept’s length measured along the hole. If the hole crosses the mineralised zone at an angle, the zone’s true thickness is less.
Duplicate: A second assay of the same sample, taken at a stage of sample preparation, to check precision. Data health counts the duplicate pairs.
Export workbook: The Excel file Strip Logs reads: one sheet per view of the drillhole database (Collar, Survey, Geology, Assays …). See Input format.
FGDC pattern: A rock pattern from the US Federal Geographic Data Committee’s geologic map standard: dots for sandstone, Vs for tuff, crosses for granite. The lithology column draws one over each rock’s colour.
Gram-metres (g·m): An intercept’s width times its grade. It compares intercepts of different shapes: 2 m at 10 g/t and 10 m at 2 g/t both hold 20 g·m.
Grid: The coordinate system a collar is on: a map projection such as UTM, or a local mine grid. A local grid is tied to a map grid by pickup points, points known in both.
Including: A richer part inside an intercept, found with a higher cut-off: “6.0 m @ 5.56 ppm Au from 16.0 m, including 1.0 m @ 27.6 ppm from 20.0 m”.
Intensity ramp: The colours, pale to dark red, for a field that grades from none to intense, such as an alteration intensity. Stronger is always darker.
Intercept (significant intercept): A stretch of hole worth reporting, written as width, grade and depth: “6.0 m @ 5.56 ppm Au from 16.0 m”. It depends on the cut-off, minimum width, maximum dilution and top cut used.
Interval: A stretch of hole from one depth to another (FROM and TO), with a value: a sample, a lithology, an RQD run. Intervals are drawn as blocks or steps on the log.
Lithology: The rock type, as logged. The lithology column draws each interval in its rock’s colour and pattern, with its name.
Log priority (logging priority): Which logging of a hole is drawn, when it was logged more than once. The lowest PRIORITY is the site’s preferred logging; the log never mixes loggings in one column.
Log scale: An axis spaced by powers of ten (0.01, 0.1, 1, 10). Grades span several orders of magnitude, so assays are drawn on a log scale by default.
Paste damage: Changes a spreadsheet makes to data when it is copied: hole 000123 turned into the number 123, a code read as a date. Data health looks for it.
Point reading: A value logged at one depth rather than over an interval, such as a structure or a magnetic susceptibility reading. The database may store it as an interval of 1 cm or less.
QC status: Whether an assay passed the laboratory’s quality control, from its PRIORITY in the database: 1 passed, 2 pending, 3 or more failed. A sample shown with only a pending or failed result is shaded amber or red on the log, and doesn’t count as grade in intercepts.
Recovery: The percentage of a drilled run that came back as core. Low recovery marks broken ground, and less core for the assays.
RQD (rock quality designation): The percentage of a drilled run made up of core pieces 10 cm or longer. Low RQD marks broken or weak rock.
Scale (1:200): How much the log is reduced on paper: at 1:200, 1 mm of paper is 200 mm of hole, so 1 m of hole takes 5 mm. Logs at the same scale can be compared side by side.
Standard (CRM): A certified reference material: material of known grade sent with the samples to check the laboratory’s accuracy. Data health counts them and says when their certified values are missing.
Strip log: A drawing of a drillhole as columns side by side on one depth scale: lithology, alteration, assays, structures, rock quality.
Structure type: What a structure reading is: a joint, vein, fault, foliation, contact. Each type has its own colour and line on the log, guessed from its name and changeable under Structure styles.
Survey: Measurements of a hole’s azimuth and dip at depths along it. A hole bends as it is drilled, so its orientation changes with depth; the header gives the first survey.
Template: The log’s layout, saved as a file: column order, widths, headings and styles, the header fields, company, title, logo, footer and paper. One template drives the screen and the PDF.
Top cut: A ceiling put on very high values before averaging, so one exceptional sample doesn’t make a whole intercept look rich.