Applied mineral exploration methods, hydrothermal fluids, baro-acoustic decrepitation, CO2 rich fluids #
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Exploration of the Mt. Boppy Au deposit, NSW

Forensic tests on soil samples

Gold at Okote, Ethiopia

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Do IOCG deposits form from CO2 fluids?

How CO2 inclusions form from aqueous fluids (UPDATED)

Understanding heterogeneous fluids : why gold is not transported in CO2-only fluids

Gold-quartz deposits form from aqueous - CO2 fluids: NOT from CO2-only fluids


Discussions why H2 analysis by mass spectrometry is wrong



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Kalgoorlie Au data

Sangan skarn Fe deposits, Iran

New models 205 & 216 decreptiometer

Studies of 6 Pegmatite deposits

A study of the Gejiu tin mine, China


Exploration using palaeo-hydrothermal fluids

Using opaque minerals to understand ore fluids


Understanding baro-acoustic decrepitation.

An introduction to fluid inclusions and mineral exploration applications.



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Ballarat Workings - Drill samples

"Blind" interpretation


This initial interpretation was done in the complete absence of any geological information on the samples, not even their drillhole number and depth. An attempt was made to group the decrepigrams based on the position of peaks in the range from 400 C to 530 C. The low temperature CO2 peaks (around 250 C) were not used in this grouping.
 

Summary

The groupings show no correlation with the subsequently provided Au analyses of the samples, or with the drillhole number and downhole depth. It is unclear if there is any geological significance in these groupings.  Although 4 separate groups were defined (including 29 of the samples),  19 of the samples remained unclassified. The differences between the groups are quite subtle and would it would be difficult to confidently use these groupings in an exploration context.

Attempting to interpret decrepitation results in the absence of sample location information is difficult to impossible and the resulting interpretation may be misleading.  No useful conclusions can be drawn from this attempted interpretation.

A separate interpretation was done following the provision of partial geological data.
 
 

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After this interpretation, the following sample cross section information was provided. Cross sections for the other drillholes were never provided.

Cross Section of BDD4 series of drilling, Ballarat
Between Britannia and First Chance shafts.

Showing sample locations, sample numbers and down-hole depths.





Group 1

Peaks at 450 C and 520 C

Run g1859, Sample NG12207, BDD2D   464.8-465.8    0.44  Au   unmineralised qtz
      Milky wh qz, weakly fractured,     ACID WASHED
Run g1838, Sample NG12212, BDD3B 654.7-655.8   .06 Au   unmineralised qz
      Milky wh qz, very weakly fractured
Run g1864, Sample NG12215, BDD4A 648.5-649.4   275.0 Au   mineralised qz
      Milky wh qz, not fractured,    ACID WASHED
Run g1867, Sample NG12221, BDD1A 467-468   28.5 Au   mineralised qz
      Milky wh qz, weakly fractured, minor vugs,    ACID WASHED
Run g1871, Sample NG12226, BDD1C 547.5-548.6   4.5 Au   mineralised qz
      Milky wh qz, very fractured, very sericitic, CO3=,    ACID WASHED
 
 

Group 1 continued.

Run g1845, Sample NG12227, BDD2A 650-651.2   0.15 Au   unmineralised qz
      Milky wh qz, not fractured
Run g1873, Sample NG12229, BDD2D 245.0-245.7   2.48 Au   mineralised qz
      Milky wh qz, weakly fractured,     ACID WASHED
Run g1875, Sample NG12231, BDD2E 238.9-240.1   11.3 Au   mineralised qz
      Milky wh qz, very fractured, much CO3=,    ACID WASHED
Run g1876, Sample NG12232, BDD2E   238.2-238.9    <0.02  Au   unmineralised qz
      Milky wh qz, weakly fractured, minor CO3=,     ACID WASHED
Run g1881, Sample NG12243, BDD5 261.0-261.6    0.03 Au   unmineralised qz
      Milky white qz, weakly fractured,    ACID WASHED
 


Group 2

Peaks at 400 C,  460 C and 520 C

Run g1834, Sample NG12201, BDD1   542-543    17.0 Au   mineralised qz
      Milky wh qz, weakly fractured
Run g1835, Sample NG12204, BDD1 549-559   .05 Au   unmineralised qz
      Milky wh qz, moderately fractured
Run g1858, Sample NG12205, BDD1 555-556  7.6 Au   mineralised qz
      Milky wh qz, weakly fractured, brecciated,   ACID WASHED
Run g1836, Sample NG12206, BDD1 561-562   13.9 Au   mineralised qz
      Milky wh qz, weakly fractured
Run g1861, Sample NG12210, BDD4 646.5-647.5   13.3 Au   mineralised qz
      Milky wh qz, very weakly fractured,    ACID WASHED
Run g1862, Sample NG12211, BDD3B 649.3-650.4   .03 Au   unmineralised qz
      Milky wh qz, very weakly fractured,    ACID WASHED
 
 

Group 2 continued.



 

Run g1865, Sample NG12218, BDD2A 243.6-244.6   120.0 Au   mineralised qz
      Milky wh qz, weakly fractured,    ACID WASHED
Run g1872, Sample NG12228, BDD2C 534-535   <0.02 Au   unmineralised qz
      Milky wh qz, not fractured, much  CO3=,    ACID WASHED
Run g1846, Sample NG12233, BDD3A 461.4-461.9  .05 Au   unmineralised qz
      Milky wh qz, weakly fractured
Run g1852, Sample NG12240, BDD4B 573.7-574.2  16.8 Au   mineralised qz
      Milky wh qz, moderately fractured, very white
Run g1879, Sample NG12241, BDD4C 476.6-477.3      0.13 Au   unmineralised qz
      Milky wh qz, weakly fractured,    ACID WASHED
Run g1851, Sample NG12247, BDD5B   266.4-267.4    0.04 Au   unmineralised qz
      Milky wh qz, weakly fractured
 


Group 3

Peak at 430 C and lacking a peak at 510 C

Run g1840, Sample NG12216, BDD2A 263.3-264.3   .14 Au   unmineralised qz
      Milky wh qz, moderately fractured
Run g1847, Sample NG12234, BDD3A 461.9-462.8  7.8 Au   mineralised qz
      Milky wh qz, rarely fractured
Run g1880, Sample NG12242, BDD5 251.9-252.9    <0.02 Au   unmineralised qz
      Semi translucent qz,    ACID WASHED
Run g1853, Sample NG12246, BDD5A   253.6-254.3    <0.02  Au   unmineralised qz
      Milky wh qz, not fractured
 


Group 4

Peaks at 420 C and 450 C and lacking a peak at 490 C

Run g1855, Sample NG12202, BDD1 537-538  .24 Au   unmineralised qz
      Milky wh qz, weakly fractured,    ACID WASHED
Run g1860, Sample NG12208, BDD3B 653.5-654.6   .02 Au   unmineralised qz
      Milky wh qz, very weakly fractured,    ACID WASHED
Run g1843, Sample NG12219, BDD2A 232.81-233.3   <.02 Au   unmineralised qz
      Milky wh qz, not fractured, clean white
 


Ungrouped


Run g1856, Sample NG12203, BDD1 550-551  <.02 Au   unmineralised qz
      Milky wh qz, very few fractures,    ACID WASHED
Run g1837, Sample NG12209, BDD4 655.3-656.2   220 Au   mineralised qz
      Milky wh qz, weakly fractured
Run g1839, Sample NG12213, BDD3B   477.1-478.1    0.05 Au   unmineralised qz
      Milky wh qz, not fractured
Run g1863, Sample NG12214, BDD4A 644.0-644.4   21.6 Au   mineralised qz
      Milky wh qz, not fractured,    ACID WASHED
Run g1841, Sample NG12217, BDD2A 255.1-256.1   <.02 Au   unmineralised qz
      Milky wh qz, not fractured
 
 

Ungrouped



 

Run g1866, Sample NG12220, BDD1A 493-494   5.6 Au   mineralised qz
      Milky wh qz, not fractured,    ACID WASHED
Run g1868, Sample NG12222, BDD1A 479-480   .07 Au   unmineralised qz
      Milky wh qz, very fractured, sericitic, much CO3=,    ACID WASHED
Run g1869, Sample NG12223, BDD1B 451.5-452.5   43.0 Au   mineralised qz
      Milky wh qz, very fractured, sericitic,     ACID WASHED
Run g1844, Sample NG12224, BDD1B 454.4-455.4   3.43 Au   mineralised qz
      Milky wh qz, weakly fractured
Run g1870, Sample NG12225, BDD1B 456.8-458.0   0.22 Au   unmineralised qz
      Milky wh qz, weakly fractured,       ACID WASHED
 
 

Ungrouped


Run g1874, Sample NG12230, BDD2D 245.7-246.1   0.02 Au   unmineralised qz
      Milky wh qz, not fractured,     ACID WASHED
Run g1848, Sample NG12235, BDD3A 473.9-474.9  1.76 Au   mineralised qz
      Milky wh qz, weakly fractured, trace S=
Run g1849, Sample NG12236, BDD3A 472.8-473.9  .04 Au   unmineralised qz
      Milky wh qz, intensely fractured
Run g1877, Sample NG12237, BDD3B   474.2-475.2      1.85  Au   mineralised qz
      Milky wh qz, weakly fractured, much CO3=,     ACID WASHED
Run g1850, Sample NG12238, BDD3B 477.1-478.1  .05 Au   unmineralised qz
      Milky wh qz, weakly fractured, clean quartz
 
 

Ungrouped


Run g1878, Sample NG12239, BDD4B 567.8-568.8   16.5 Au   mineralised qz
      Milky wh qz, very fractured,    ACID WASHED
Run g1882, Sample NG12244, BDD5A 240.2-240.75     6.2 Au   mineralised qz
      Milky white qz, moderately fractured,    ACID WASHED
Run g1883, Sample NG12245, BDD5A 245.5-245.95     0.02 Au   unmineralised qz
      Milky white qz, moderately fractured,    ACID WASHED
Run g1854, Sample NG12248, BDD5B   258.9-259.9    30.0  Au   mineralised qz
      Milky wh qz, weakly fractured
 

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