1887
ASEG2004 - 17th Geophysical Conference
  • ISSN: 2202-0586
  • E-ISSN:

Abstract

Mining of the Broken Hill Ag-Pb-Zn deposit has substantially modified what was originally a positive anomalous mass. When an airborne gravity gradiometer (AGG) survey was flown over the Broken Hill region in early 2003, the measured response reflected the modified mass distribution. To answer the questions "What was the original response of the orebody?" and "Would this response have been detected had the survey been flown prior to mining?", an estimate of the changes in response brought about by mining activities was made and added to the survey data to produce an image of the pre-mining gravity response.

To estimate the change in response, a 3D model of the mined portion of the deposit was built. An estimate of the change in mass due to mining activities was made and this mass was distributed with uniform density throughout the model. The gravity and vertical gravity gradient response of the orebody model was then calculated, filtered to match the characteristics of the AGG data and added to the observed survey data.

The ‘corrected’ data show distinct gravity and gravity gradient highs over the northern and southern parts of the orebody which hosted the bulk of the reserves. Although the anomalous response is close to the noise levels of the survey data, we can conclude that the AGG survey would have detected an anomalous response from the Broken Hill orebody had the survey been flown prior to mining. However, there are other geological features in the survey area that produce similar anomalies, notably a number of amphibolite units.

© ASEG 2004
Loading

Article metrics loading...

/content/journals/10.1071/ASEG2004ab083
2004-12-01
2026-01-23

  • From This Site

    /content/journals/10.1071/ASEG2004ab083
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Dransfield, M.H., 1994, Airborne Gravity Gradiometry: PhD. thesis, University of Western Australia (unpublished).
  2. Dransfield, M., Christensen, A., Rose, M., Stone, P., and Diorio, P., 2001, FALCON test results from the Bathurst Mining camp: Exploration Geophysics, 32, 243-246.
  3. Haydon, R.C., and McConachy, G.W., 1987, The stratigraphic setting of Pb-Zn-Ag mineralisation at Broken Hill: Economic Geology, 82, 826-856.
  4. Hensley, C, 2003, Data processing report, Airborne Gravity Gradiometer Survey, Broken Hill, NSW, Australia: BHPBilliton Falcon Operations Report CR 10657 for Survey USN 142911122002.
  5. Johnson, I.R., and Klingner, G.D., 1975, Broken Hill ore deposit and its environment: pp. 476-491 in Knight, C.L. (ed.), Economic geology of Australia and Papua New Guinea: The Australasian Institute of Mining and Metallurgy (AusIMM), Monograph 5, vol 1 (Metals), 1126 pp.
  6. Kelly, J.J, and Bell, I.F., 1992, Economically mineable resource in an underground metalliferous mine: Australasian Institute of Mining and Metallurgy Conference, 1992, 141-151.
  7. Lane, R., Milligan, P., and Robson, D., 2003, An airborne gravity gradiometer survey of Broken Hill: pp. 89-92 in Peljo M., (compiler), Broken Hill Exploration Initiative: Abstracts from the July 2003 Conference: Geoscience Australia Record 2003/13.
  8. Li, Y., and Oldenburg, D.W., 1998, 3-D inversion of gravity data: Geophysics, 63, 109-119.
  9. Maidment, D.W, Schmidt, P.W., Giddings, J.W., Peljo, M., and Clark, D.A., 1999, A petrophysical dataset for the Broken Hill region: AGSO Record 1999/50.
  10. Murray, A.S., 1997, The Australian National Gravity Database: AGSO Journal of Australian Geology & Geophysics, 17, 145-155.
  11. Pecanek, H., 1975, Interpretation of geophysical data from the Broken Hill area: MSc thesis, University of Adelaide (unpublished).
  12. Traicos, J., 2002, Quarterly report for the period ending 31 March 2002: Report to the Australian Stock Exchange by Perilya Limited, dated 26 April 2002.
  13. Tucker, D.H., 1983, The characteristics and interpretation of regional magnetic and gravity field in the Broken Hill district: Australasian Institute of Mining and Metallurgy Conference Series, 12,81-114.
/content/journals/10.1071/ASEG2004ab083
Loading
  • Article Type: Research Article
Keyword(s): airborne survey; Broken Hill; density; gravity gradient; mining

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error