Ground Geophysics Reporting

REQUIREMENTS FOR GROUND GEOPHYSICAL WORK REPORTS SUBMITTED TO EXPLORATION AND MINING DIVISION

The following “Requirements for Ground Geophysical Work Reports” are supplementary to the “General Reporting Requirements”, as included in the “Mineral Prospecting Licence Terms and Conditions”. There are separate requirements for Airborne Geophysical Surveys.

If the Licensee uses a contractor to carry out the geophysical surveying, or to process or interpret data, the Licensee is required to notify the contractor of these requirements and to ensure that the contractor adheres to them.

GENERAL:

A variety of geophysical techniques are used in exploration for minerals. Irrespective of the technique used, presentation of the raw data and results should follow the following format.

REPORTS:

All reports on geophysical work should include the manufacturer's name, model and a summary of relevant technical specifications of geophysical equipment used.

All the geophysical measurements should be listed in a tabular form such that in the case of linear traverses, data along each traverse should be separated by a header "line number ...." followed by the table containing X,Y (National Grid Co-ordinates), station number and the geophysical parameter(s) measured along that traverse e.g. gravity, magnetic, resistivity, etc., together with the relevant units of measurement.

Information on survey parameters (line and station spacing, measuring frequency, etc.), methodology in general and the specific field technique used should also be provided.

All the data, raw and processed, should be provided in analogue (paper records) and digitally, in ASCII format on CD ROM. In the case of random data, an arbitrary line number should be used as a "header".

Separate sections should deal with the interpretation and assessment of the data and the basis for conclusions reached should be stated.

If physical properties of rocks are measured (e.g. rock density, magnetic susceptibility, electrical resistivity), full details of the results as well as information on rock type, sample location (National Grid Co-ordinates) and depth, method used, should all be provided.

MAPS:

  • Maps should be on an appropriate standard metric scale e.g. 1:25,000, 1:50,000.
  • Maps should have the National Grid Co-ordinates.
  • Maps should have a north arrow and a bar scale.
  • Maps should clearly indicate sufficient details about the type of geophysical survey e.g. gravity, magnetic, etc. together with information on the person/contractor responsible for the work.
  • Maps should have traverse lines and points of observation clearly marked and identified.
  • Maps should include the PL boundaries and numbers, and adequate geographical information.
  • Digital grids should be in Ascii or Geosoft format, and maps of the grids should be in geo-referenced Geosoft compatible format.
  • Specific Geophysical Techniques:

    An Industry standard format should be followed to provide all information to enable a full interpretation of the data. In addition, the following approach should be used for gravity or magnetic surveys.

    Gravity Surveys:

    A local base station made in the course of the survey should be tied into the National network of base stations (DIAS) using the nearest National base station, information on which can be obtained from the Geological Survey of Ireland. Results of topographical surveying, if carried out, should be provided in map form.

    Magnetic Surveys:

    Depending on the size of the area and the instrumentation used, a local base station reading should be recorded as frequently as is appropriate. Where no dedicated base station magnetometer is used, arrangements should be made for diurnal corrections by, for example, reoccupying the base station at appropriate intervals or using third party magnetograms.

    1st December 2004

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