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OGX'S-High GradeTailings-Historical Overview, page-3

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ozbucheron

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347

08/07/18

10:38

Post #: 34210635
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Originally posted by Saltiga62 ↑

G'DAY -Retoors & all -Below is an overview from what was occurring ATT,
where & when the information in the quarterly you have referred to- originated from,
& all additional information pertinent up until the present time.

Independent Testwork Confirms High Gold Grades and

Recoveries at Cascavel Gold Mine

Successful test work programme undertaken by Hazen Research Inc.
Asx Ann ASX/Media Release – 01 June 2017 -
Independent Testwork Confirms High Gold Grades & Recoveries

ASX/Media Release – 01 June 2017 Grade Determination
Grade determinations were carried out on each of the samples (see Table 1) with the test work programme confirming the high-grade nature of the Cascavel lode system with both the underground samples returning exceptionally high head grades:
Sample 3934-79 (HRI # 54742-1) Head Grade = 37.1 g/t Au
Sample 3934-80 (HRI # 54742-2) Head Grade = 48.7 g/t Au.
The assays of the process plant tailings samples confirmed that the Cascavel processing plant was recovering gold from the feed and not losing excessive gold to the tails:
two (2) x 75kg tailings samples from the process plant TSF (3934-81 and 3934-82).
Sample 3934-81 (HRI # 54742-3) Grade = 0.9 g/t Au
Sample 3934-82 (HRI # 54742-4) Grade = 1.6 g/t Au.

Following the suspension of operations at the Cascavel in Q4 2016, Orinoco contracted
Hazen to evaluate:

• two (2) underground gold ore samples (from both the northern and southern areas of the Cascavel mine) to confirm both the gold content of the Cascavel system and the gravity recoverability of the gold within the system; and

two (2) samples of tailings material from the Cascavel processing plant tailings storage facility (TSF) to verify gold recoveries.

So the above states that :Quote
Results provide independent Validation of high-grade nature of the
Cascavel lode system.
Confirmation that Cascavel ore is highly (>90%) amenable to gravity recovery.
So independent results confirm the high-grade nature of the Cascavel lode system at Cascavel .
It also states the following 　
The opportunity was also taken to undertake preliminary assessment of the leachability of the Cascavel ore with a
view to the possible future addition of a leaching circuit to the Cascavel processing plant. 　
The Gravity Recoverable Gold (GRG) evaluation showed that 98–99% of the gold in the underground samples could be
recovered into 2–3% of the weight.
The process plant tailings showed that 92–94% of the gold could be recovered into approximately 3% of the weight.

Interesting comment that tailing were also evaluated to establish the amount of gold that could be recovered
from tailings.
So the tailing samples were 75 kg's each not bulk samples ( 1,000kg) which would give even better representation though a sample is a sample their is no reason to doubt the labs analysis whatsoever .
So the plant is shut down at this time
Orinoco’s Chief Executive Officer, Mr Craig Dawson, said; "These results confirm both the Company’s previous metallurgical testwork
programmes and the applicability of the design of the existing processing plant as we progress our plan to re-commence production at Cascavel.
This gives us confidence in the other improvements we are implementing at Cascavel, particularly the revised mining strategy we have outlined,
which is aimed at reducing dilution (and thus increasing the head grade) and increasing productivity".

The real issue is- the operational differential between head grade & Gold Recoveries .
The plant was shut down for this reason as it was uneconomical to run- recoveries were dismal.
Recommendations made by consulting experts during the original commissioning period were not
implemented-that was to replace the tertiary crusher with a small ball mill so as to crush the ore to
a smaller micron & enhance the liberation of gold.

Upon recommencements of operations-processing operations recommenced on a single
shift basis on 28 August 2017.
　
ASX/Media Release – 21 September 2017 -Operations & Corporate Update and Appendix 3B

Successful small-scale stoping trials using new method implemented improving dilution
while mining, so head grade is even higher- Note plant through-put also increased
Quote-
The average throughout rate since the recommencement of processing operations
has been 22 tonnes per hour, which is in excess of the budgeted throughput rate of
15 tonnes per hour.

So we have less dilution ( higher head grade )& tonnage through-put
increase of 46%.
THIS SHOULD RESULT IN HIGHER GOLD RECOVERIES ?
Note: So remember production re-commenced 28th August 2017
Then in the quarterly-ASX/Media Release – 31 October 2017
Quarterly Activities Report - September 2017
Quote-
Process plant feed will continue to be predominantly low-grade ore for Q4 .
The Company has received assay results from the external laboratory and a summary of the process
plant production since the resumption of processing to the end of the quarter is outlined below.
Throughput rates being above the nameplate capacity (approximately 21 tonnes per hour actual
vs 15 tonnes per hour nameplate);
Average tailings grades being consistently lower than those recorded in 2016 (≈0.5 g/t Au 2017 vs1.0 g/t Au 2016);
A more representative set of results will become available once the performance of the plant has been
assessed with the introduction of more stoping ore from late in Q4 onwards.
Success of sluice box with approximately 5 – 10% of gold recovered being captured by the sluice box gold which would have
previously been lost to tails.

Important
Through-put 21 tonnes per hr.
Head Grade 1.7 grams per tonne.
Tailings grade 0.5 grams per tonne.
Leaves recovered gold at 1.2 g p/t x 21 t per hour = 25.2 grams per hour.
x 5 hrs per day run time ( single 6 hr shift allows 1/2 hr shut down & start up).

WOW a grand total of 126 grams per day x 20 day's run time per month
equates to a grand total of 81 OZ x $1,700 AU-POG per month as revenue
of -$137,749AU per month ?
SO LETS GET THIS STRAIGHT at a feed grade of only 1.7 grams per tonne the gravity plant is being run with-out any possibility of meeting AISC,ALL IN SUSTAINING COSTS & HAS NO CHANCE OF DERIVING ANY POSTITIVE CASH FLOW ! & IT IS BLEEDING THE COMPANY'S CASH RESERVES DRY !
It does not get better from here !
So does it really add up that the gravity plant would be supplied, with such low grade ore for such an extended period of time ?
There is little doubt the resulting trajectory path had it continued could have either resulted in OGX becoming insolvent or taken over .
It seems to be incredibly irresponsible- to continue with such low grade feed OR a much higher Grade was being supplied than that which was being reported ATT to market.
At the time of MGT change the gravity plant had run for 112 day's-16 x weeks.
Board spill occurs-Change of BOD & Key MGT.
Asx Release 18th Dec 2018-Corporate and Operations Update 　
Focus on Reducing Costs and High-Grade Production.
Re-Organisation of Board and Senior Management.
Cost cutting overhead and operational costs both in Australia and in Brazil . Focus on high grade gold production.
Completion of $1.8m Capital Raise to existing and new sophisticated investors.
Performance Rights to be issued to Directors and Senior Management in lieu of directors fees and salaries.
Why do we think the BOD spill & key MGT changes occurred ?
Why was it one of the first things the new BOD-ATT- current MGT did was to sample tailings ?
Re-release of Orinoco Outstanding Grades of Gold in Tailings　
Orinoco Gold Limited (ASX: OGX) (Orinoco or the Company) is re-issuing the announcement dated 31 January 2018 titled Orinoco Confirms Outstanding Grades of Gold in Tailings.
This announcement includes further disclosure including a Competent Person sign off and Table 1 required under the JORC code.
The body of the announcement is unchanged from the original release.
What of revelations from the new BOD & MGT.
Quoted from Asx Release
This test was conducted on one of the Company’s dry stacked tailings stockpiles and was directed
by our geological team.
The one tonne samples were taken at depths of up to 4 metres and included two vertical channels.
Five (5) samples extracted in random one-tonne batches have been processed through the 400kg
per hour Hammer Mill 2 and recovered a total 46.37 grams of gold.
The samples returned an average grade of 9.27 g/t.
The milling process is recorded with CCTV and monitored by senior staff to ensure process integrity.
Final processing is carried out in the gold recovery room under rigid security controls and accompanied
by the departmental manager.

Comment from COO
Chief Operating Officer, Richard Crew commented "In my 30 years in the mining business I have only seen one other project with such high tailings results.
Current OGX -MGT Asx Release
Quote--Importantly THIS STOCKPILE was NOT from the MATERIAL PROCESSED from the Higher Grade MESTRE ZONE -that we suspect has GONE TO TAILS ALSO.

Additional Asx Release-This MSM sample of previously 100 tonne processed-Batch taken from
the tailings re-sampled returned a grade of 26.64 g p/t.
When it was processed through the gravity plant returned 2 g p/t.
So at mill feed to the gravity plant must have been at or about 33 g p/t-ATT-deduct 2 g p/t the gravity plant recovered =31g p/t going to tails, when resampled & processed through the small gravity mill at 85% recovery equates to the actual resampled result of 26.64 g p/t.
Note :this equates to 6% recovery with the gravity plant & 94% going to tails.
This likely head grade of 33 g p/t is also aligned with what the independent head grade was determined
to be by by Hazen Research Inc.
There is virtually no doubt about perceived head grade given the previous MGT & the independent review undertaken by
Hazen Research Inc at 37 & 48 g p/t.

ASX/Media Release – 01 June 2017 Grade Determination
Grade determinations were carried out on each of the samples (see Table 1) with the test work programme confirming the high-grade nature of the Cascavel lode system with both the underground samples returning exceptionally high head grades:
Sample 3934-79 (HRI # 54742-1) Head Grade = 37.1 g/t Au
Sample 3934-80 (HRI # 54742-2) Head Grade = 48.7 g/t Au.
These head grades are further supported by numerous one tonne samples ( not panel samples) also conducted by current MGT.
There has been some confusion recently of tailings grade it was quoted at the mining 121 presentation in London by M.D.-J.G as being 9-84 grams per tonne.
Quoted Transcript Below (time = time into video)

Time-1 min -We have TAILING THAT ARE GRADING SOMEWARE BETWEEN 9 g p/t- 84 g p/t.
Time 2.49 min-We have a fourth Hammer Mill Arriving at the end of the month, that WILL BE DEDICATED ONLY-TO PROCESSING TAILINGS at 9 grams & upwards that will probably be
$50.00 per Ounce Production.
Its just way to compelling given all of the above to say its all coincidence head grade has been independently
verified & further both previous MGT & current MGT are all in the same ball park regarding mill grade
head grade further supported by approx. 30 plus one tonne bulk samples by current MGT.

This is very important not just regarding future plant feed -but regarding tailings average grade .
So as the Gold did not evaporate given all above & more where do we think the Gold Went ?
Understand only a minority of OGX holders have operational comprehension though logic should surely apply.

Head grade -mill feed has been verified many times at over 30 grams per tonne ,its the differential between
tailings & mill feed grade that determines expected recovery-the differential is just way to high for it to
have gone any where else but to tailings.

A couple of one liners trying to state otherwise just does not cut it when the overwhelming amount of
information to the contrary from many different sources are taken into account.
Hence it very Obvious the Gold is in the tailings .
I have spent a great deal of time researching & compiling above as it is important & have given references where possible, certainly enough info provided for those interested to do additional research & or to verify the information for themselves.
Can't help the length of the post as its all information pertinent.
imo-and due to all of above inline with many other opinions.
gltah-salt

Expand

A few points:

- sample grade is not head grade. Dilution in development is significant and dilution in stoping will occur but will be less.
- by far the majority of tonnes mined have been from development.
- had the vein thickness or sample thickness been provided with the sample grade an estimate of dilution would have been possible.
- no statistical analysis has been done of the sample assays. It may not be valid to simply take the average of all assays - top cuts are typically applied to moderate the influence of high grade outliers.
- no doubt there is gold in the tails - average 4.12 g/t in the announcement of 9/12/16 from 7,000 tonnes.
OGX Price at posting: 6.7¢ Sentiment: Hold Disclosure: Held
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