SL MINERADORA
LTDA
BY: LUIS
FERNANDO SANTANA DA SILVA GEOLOGIST
Final
Exploration Report
3RD
EDITION
DESCRIPTION OF
THE AREA
PROCESS: DNPM No 867.231/95
EXPLORATION
LICENSE: No 2.651/98
REQUIRED
MINERAL SUBSTANCE: DIAMOND AND GOLD
ECONOMICAL
MINERAL SUBSTANCE: DIAMOND
LOCATION: SรO LUIS RIVER BASIN
MUNICIPALITY: JUอNA MT
TECHNICIAN IN
CHARGE:
GEOLOGIST
/ GEOPHYSICIST LUIZ FERNANDO S. S.
1
PROCESS IDENTIFICATION
2
HOLDER IDENTIFICATION
3
LOCATION OF THE AREA
4
DESCRIPTION OF THE AREA
1
GENERALITIES
2
INFRASTRUCTURE
1
PLANNING
1
EXPLORATION MESH
2
GEOLOGY OF THE AREA
3
GEOTECHNICAL DRILLING OF LOW DEPTH
4
GEOTECHNICAL DRILLING OF MEDIUM DEPTH
5
VOLUMETRICAL EVALUATION
6
CHARACTERIZATION OF THE DEPOSITS
7
CHARACTERISTICS OF MINERALIZATION
8
SAMPLES AND VOLUMETRICAL TREATMENTS
9
OCURRENCE OF GOLD
10
OTHER MINERAL GOODS
11
NEXT WORK TO BE DONE
1
CONTENTS
2
METHODOLOGY OF CALCULATION OF RESERVES
3
QUANTIFICATION OF THE DEPOSITS RESERVES
1 EVALUATION OF THE GEOLOGICAL-GEOPHYSICAL-GEOMETRICAL PARAMETERS
2
MINERAL EXPLORATION DATA INVENTORY
3
GRADE FROM DRILL HOLES
1
ECONOMY
2
MINE PLANNING
PART IX:
BIBLIOGRAPHY
PART X:
ATTACHED ITEMS
1
MAPS
2
DOCUMENTS
1
PROCESS IDENTIFICATION
1.1 Process
nบ - 867.231/1995
1.2
Exploration license nบ - 2.651/1998
1.3
PUBLICATION DATE ON DOU 11/11/1998
1.4
PUBLICATION DATE OF THE DESCRIPTION OF THE AREA 10/12/04
1.5
REQUIRED MINERAL SUBSTANCE Gold and
Diamond
1.6 EXPLORED
MINERAL SUBSTANCE Gold and Diamond
1.7 MINERABLE
MINERAL SUBSTANCE Diamond
2
HOLDER IDENTIFICATION
2.1 HOLDER: SL Mineradora Ltda.
2.2 ADDRESS
2.2.1 Matrix .......
2.2.2 Correspondence
.......
2.2.3 Enterprise.......
3
LOCATION OF THE AREA
3.1 TERMS OF THE AREA
Sใo Luis River Basin. It is located at the 1st
Phase of Juํna Project, Juํna MT, and inserted in the
important Mineral Diamondiferous Province, including the Drainage Basins of Sใo
Luis and Juininha Rivers as well as their tributaries of 3rd order.
3.2 ACCESS
The access via road is by Federal Motorway BR-174 (Juํna-MT
to Vilhena-RO Motorway) until KM 30 turning right by Linha 03 until KM 10 and
then through an extension to the right for 1 km until Sใo Luis Farm, SW to the
area in Sector 1. See maps SLML 01 and
SLML 02 below.
3.3 MUNICIPALITY: Juํna
3.4 STATE: Mato Grosso
3.5 AREA IN HECTARES:
1,889.13.
4 DESCRIPTION OF THE AREA
The area belonging to SL Mineradora LTDA in reference to DNPM-MT Process nบ 867.231/95,
according to the new adequacy published on D.O.U in 10/01/2005 is 1,889.13
hectares.
-
Effectively
exploration area: 1,889.13 hectares;
-
Diamond
mineral deposit limit area: 1,889.13 hectares
The area is delimited by a polygon with a vertex at
8,245 m (Vertex 1) on the true direction of 33บ20 NW, at the reference point
with geographical coordinates of:
.....South
Latitude
.... West
Longitude
The delimitating polygon of the area has 10
vertexes, which, from Vertex 1,
and covering if clockwise presents the following sides with lengths and
true direction in Table 01 below:
FROM VERTEX /
TO VERTEX / LENGHTS / DIRECTIONS
1
GENERALITIES
1.1 INTRODUCTION
AND RECORDS
SLML SL
MINERADORA LTDA is the holding company of the area of 1,889.13 hectares covered by
Exploration License nบ 2.651/98 in reference to DNPM Process nบ 867.231/95,
according to records in Table 02 below, qualified to explore diamond and gold
in Aripuanใ Province, Juํna, Mato Grosso.
DNPM MT INSPECTION
TECHNICIANS / INSPECTION DATE / ADEQUACY DATE OF PUBLICATION ON D.O.U. /
ADEQUATED AREA (ha)
This work corresponds to the 3rd Edition of the Final Exploration Report, containing
the results of geological-geophysical exploration work performed by SLML until January/2005, fulfilling the
DNPM requirements, after the publication of the Description of the Area on the
D.O.U.
The procedure of new calculation of the area
deposits reserves was mainly due to the following factors:
- Final resolution of divergence in limits of area
which resulted in the publication of the Description of the Area, establishing
the a surface of 1,889.13 hectares, which made the polygon of cubed area be
altered;
- The resignment of the Approval Area of 40
hectares, given to the former owner (cancelation between SLML and Mr. Osvaldo Pires) which resulted in the addition of
gravel areas C mineralized with
diamond;
- Discovery of new anomalous areas corresponding to
the Prospect Basins with economically minerable medium grade, creating deposits
with average grades of 1.26 ct/m3.
SLML restarted its systematic
geological exploration work in Aripuanใ Province in 2000, aiming at finding new
mineralized areas in diamond and gold, specially in the basins of Sใo Luis,
Juininha and Cinta Larga rivers. Due to the heterogeneity of the mineralized
geological environment (mineralized gravel levels in secondary environment) in
Sใo Luis basin area and proximities, the works continued until January/2005
with volumetric samples and improvement tests for calculation of reserves and
real grades.
In November/2000, SLML performed a ground mag, covering specially Sectors 1 and 4, as
part of an ample mineral exploration program in the region and area. This
research became a basic and defining tool of the structural families which
conserve mineralized horizons out of surface visual range. Aimed at specific
targets, a radiometric intervention of total score to find hydrothermal
transformations, radiogenic anomalies and auxiliate in mapping large geological
units of the area was also performed. These geophysical data, in addition to
the verified litology (mineralized gravel levels, pipes, dikes, sills and
gaps), correlation of intrusions with structural events and anomalies of diamondiferous
gravels verified in secondary environment of low and medium depth, allowed to
conclude that the Sใo Luis River Basin is a prospect of high economical
perspective diamond, once it was proved it can be done.
From these
conclusions, in January/2001, a phase of detailed volumetric sample in
untouched secondary deposits in Sector 1 of the area was begun. The schedule
planned to measure reserves and real grades, so improvement tests in
geometrical panels supported by little investments in acquisition of machinery
and equipments, improvement of Duplicated Fixed Ramps, Fixed and Mobile Ramps,
technical training of operational workforce, improving not only the processing
quality and quantity, but also its economic, maximizing production with low
levels of loss as well as reducing cost with a better organizational control,
system electrification and acquisition of a diamond recovering machine Flow
Sort fundamental factors for the success of the project.
In December/2004, when the Description of the area
was published (10 December 2004), which definitely confirmed the Area
Polygonal, SLML performed with the
recalculation of the secondary deposits reserves of colluvial terraces,
transition areas, alluvions and paleocanals, old mineralized prospect basins,
adequating the new area, the updated reserve of SL1 deposit.
The strategic positioning of the area located in the
central part of contact between two large stratigraphic units of the region,
Craton Guapor้ and Parecis Group Sediments, awards them particular importance
to the level of creation of economical potentially reserves for diamond and
other correlated mineral goods, a fact that has been taken into account in
particular exploration programs and investments, being this positioning as
important as the existing mineral resource itself.
Along with that, the expansion of researches are
anticipated, now aimed at primary horizons and the development of mining
activities for the next years involving initially sector 1 of the area which
covers all geological-structural-magnetic systems of genetic importance of the
blocked economical resource.
The volume of mineralized gravel with diamond were
of 7,713,770 m3 with average grades of 1.6458 ct/m3 in the deposit and of 0.19
ct/m3 at the 1st level of the sedimentary package, outcome which
created a mineral grade of 12,695,325.70 ct of diamonds with varied
granulation, colors, purity, and physical-chemical classification.
Also in December/2004, a medium geotechnical probing
depth test was initiated, with the objective of defining the real thickness of
the area sedimentary package (1st and 2nd level) and the
levels of gravels C3 stored at the
base part of this profile (after the +- 12m depth clayish false bedrock).
Considering the aims of its management office, from
the investments performed in 2004, SLML
defined for the next years, as prioritary goals, the sustainability of little
investments in improvement of plants and treatment ramps, improving not only
the quality of processing, but its economy and electrification as well,
important aspects for the project feasibility in the first 10 years to come.
The present areas holder is ready to initiate an
open-air mining project guided by the Mining and Environmental Law in vigor,
for it is elaborating the PAE PLANO DE APROVEITAMENTO ECONิMICO
(ECONOMICAL UTILIZATION PLAN) and
the PROJETO
INTEGRADO DE MINERAวรO (UNIFIED MINING PROJECT) for the future phases
of the project.
For the fullfilment of the present research program,
the Specialized Department of Geology-Planning-Mining determined the command
and technical responsibility to geologist/geophysicist Luiz Fernando S.S, working for this mining company since 20th
August 2000.
The Situation (SLML
01) and Details (SLML 02) maps of the research area
follow below.
2 INFRASTRUCTURE
Area built for the Central Base Camp with
approximately 1.50 hectares of area, containing: a LFA (X-ray Sorting House) with a Flow Sort recovering diamonds at a
100% level; dormitories, refectories, garage, storage room, infirmary, security
lodge, etc. qualified technical and operational staff. 110 volts electrical
energy availability 24 hours/day and specific generating groupscapable of
generating energy from 220V to 380Volts for garage and LFA special needs, as well as water for housing supplying, LFA, garages, office, with semi
artesian wells with capacity of 2500 m3/hour each well (reservatories of
25,000 and 15,000 liters).
There is a telephoning system with DDD 66 (Long
distance call), connecting all mines to the office at the Central Camp in
Sector-1, and vsp Internet provider.
1
PLANNING
The research
methods were carefully chosen for diamond and gold, traditionally used in
prospect researches, low and medium geotechnical probing depths, wells,
trenches and volumetric tests, mainly aimed at:
a.
Determination of
thickness of sterile covering and levels of gravel C, possibly mineralized at the 1st sedimentary level;
b.
Determination of
the gravel volume in each deposit and its corresponding sterile level;
c.
Determination of
typology of levels of gravel;
d.
Correlate each
type of gravel as regards to its grade of involved mining satellites and the
present mining degree;
e.
Reserves of
studied mineralized deposits;
f.
Elaboration of the
Final Research Report.
1.1
BIBLIOGRAPHIC SURVEY
The bibliographic
surveys aimed at defining of economical prospects e elaboration of preliminary
basic plants for field checking.
1.2 INTERPRETATION OF LAND SAT IMAGE
Important auxiliary
tool for delimitating regional and local structures, lined drainage,
vegetation, among others.
1.3 ELABORATION OF BASE PLANTS
Making of maps of
land accesses and location of main drainages, preliminary grade, in adequate
scale of 1:10,000.
1.4 RECOGNITION OF ACCESSES AND CONTACT WITH LOCAL OWNERS
The verification of
land accesses to the nearest points to the access roads and obtainment of
authorization from local owners for the performance of the research work was
made obligatory.
1.5 RESEARCH MESH
Location at area
field and establishing of the differential mesh starting point, with section
breaks and specific holes for each sector, according to its
geological-geophysical-structural-geometrical characteristics. After the new
polygonal publication, adequacies at the N limits were made.
1.6 TOPOGRAPHICAL COTES SURVEY
Together with the
probing mesh magnetic surveys, the taking of cotes to level the studied
geological environment was performed, and its dimension was included in the
Geomorphological Map presented in the 1st version of the Final
Exploration Report.
1.7 GEOLOGICAL-STRUCTURAL MAPPING
The objective was
to identify the large geological units, its typologies, the related deposits of
primary and secondary degree, correlating them stratigraphically and
temporally, and reproducing in adequate scale maps.
1.8
- LOW GEOTECHNICAL DEPTH PROBING
Program to define
depths up to 12m, the shallow probing 1 mechanized auger MB 1/A, Yanmar, NG-147
model, 5 inches. The aim was the thicknesses of the studied geological
environment, trying to define the vertical and horizontal continuities of
levels of C mineralized with
diamond, and with descriptions, measurements and packing of the probing proofs.
1.9
MEDIUM GEOTECHNICAL DEPTH PROBING
A probing was
specially programmed to reach depths of up to 30m. This probing was performed
with a 3 reverse circulation rotative probe, with pole for collecting
proofs of 1m depth. The aim was the definition of thickness of the studied
environment sedimentary package, aiming at giving emphasis to the vertical and
horizontal continuities of levels of C mineralized
with diamond, specially to base levels containing mineralized thick clastics,
with descriptions, stratigraphical measurements, litological and mineralogical
analysis, and packing of C studied
levels.
1.10 TREATMENT TESTS
Over positive
prospects of the trenches, the apertures of geometrical panels were placed,
which measured 10x20m and 10x40m initially, for the calculation of volume and
grade of the studied geological environment. The panels were sequentially
opened in a parallel and longitudinal way to N, facilitating the dumping of rejects from the process of
mineralized C levels.
Following the new
panels operations, the removal of the overburden of sterile Level A1 is performed
for one side, and sterile Levels B1, B2, B3, B4 and/or B5 for another side. On
mineralized C levels, the
dismantling of the contained mass forming a humid pulp was performed, in order
to prepare for the start of extraction
process by high pressure spouts/jets and 4 hosepipes, and processing in
duplicated fixed plants PF, fixed
ramps RF and mobile ramps RM established near the dumping bowls.
1
RESEARCH MESH
SECTOR 1 / SECTOR
2 / SECTOR 3 / SECTOR 4
2
GEOLOGY OF THE AREA
The adequacy of
data of the geological-structural mapping of the area, according to the new
polygonal, ranged 56.60 linear km, covering 4 sectors, with 300 geological
stations described and reproduced in SLML
02A Map below. The geological units of the area suffered intense
manifestations derived from events which created the structural-magnetic
domains, from the following families of faults:
Family......
The positioning of
mineralized C levels is strategic
and lies in a zone which is tectonically near the contact of two large regional
units, the Fanerozoic Sediments to S
and the Meridional Portion of Craton Guapor้ to N. Five different environmental compartiments of a structural-magnetic
conotation are defined below:
2.1 BASEMENT
Formed by rocks
from the Xingu Complex, characterized by alkaline-feldsphatic granites,
strongly intemperized, as well as migmatits, local gneiss, amphibolites and
metasediments which constitute the local bedrocks. The granitic/gneissic land
have slightly wavy morphology of Archean-Proterozoic evolution which intregrate
the Craton Guapor้. There are evidences of altered basic-ultrabasic volcanic
intrusions cutting the basement, and maintaining discordant overlapped contacts
with the fluvial sediments from the Parecis Group.
2.2 INTRUSIVES
They correspond to
basic-ultrabasic volcanic rocks which form reliefs in an altered nuclear shape,
dikes, sills, cutting rocks from the granitic/gneissic basement. Its soil is
brownish red with slight yellow spots, strongly altered by intemperic physical-chemical and
hydrothermal-mineralogical effects, forming zones which are rich in
piroxenites, hornblende, chlorite and opals. In the interfaces it is found
large quantities of thick clastics mineralized with diamond due to the
formation of S2 structural traps, as
minerable prospects. They are more expressive in W area of Sector 1, where there are the dikes, sills, porphyry
dykes and kimberlitic-lamproitic nucleus,
where olivine, piroxenites, magnetite, apatite, ilmenite, cyanite, piropo
garnets and zircon are predominant.
2.3 SEDIMENTARY COVERS
It is constituted of irregular levels from Casa
Branca Farm formation, which is at Parecis group from the Superior Cetracious
Age (?) with great litological varieties and depositional environments
containing levels of C gravels
mineralized with diamond. These covers occur discordantly overlapped the
basement rocks and due to faults over mafi-ultramafic intrusives of the region.
Thus, elevated grades of thick clastics are concentrated on the serval
structural-magnetic traps from Families S1,
S2, S3 and S4 domains.
2.4 LATERITIC-DETRITAL COVERS
These form a thick
hardened lateritic crust of large linear extension which protect and hold thick
levels of C gravels mineralized with
diamond. They derive from unconsolidated sediments and/or elevation of the
granitic basement.
2.5 UNCONSOLIDATED SEDIMENTS
Originally from the
strong distal fluvial gradient and imposed to structured environments of
terraces, transition zones, modern alluvia, shallow and deep paleocanals. They
frequently appear in the fillings of structures from S1, S2, S3 and S4 domains,
forming expressive deposits mineralized with diamond, of average thickness of +-
4.30 m, with C level at +- 0.50 to
+- 1.00 m. The contact relations of the alluvial sediments with the intrusives
and Parecis group are temporally, litologically and erosively discordant.
2.6 - SรO LUIS KIMBERLITES (SS1)
They occur in
stable cratonized regions constituted of varieties of dikes and pipes relates
to S2 Structural-Magneetic System,
breccian-shaped, pipes whose extensions are controlled by deep fractures
filled with transported sedimentary materials, where it is believed to reach
asthenosphere. These intemperized materials, due to geophysical results suggest
subvertical cylindric shapes of dimensions of not more than 200x100m. On
surface they are brownish-purple intemperized masses catalogued at 10m average.
Kimberlites are
alkaline peridotites which invaded the Xingu Complex and Parecis Group
interlockings, and at the last one contaminating the base level of Casa Branca
Farm Formation.
The indicating
minerals are preferably cromo-magnesian ilmenite (pricoilmenite),
titaniferous ilmenite, chromic (green) diopside, and chromic piropo garnet,
possibly with a low Ca grade. The composition seems very changed, due to
mineralogical-hydrothermal alterations in its ascension towards surface by
acquiring mineral from different rocks crossed by the intrusion (xenolith). At
the level of superficial occurence, they are sometimes considered as microgaps
formed by peridotic paragenesis minerals, collected in different levels of the
mantle and crust.
2.7 SรO LUIS LAMPROITES (SS2)
The dark green
lamproitic masses which are saturated in silica, rich in magnesium and
potassium and different from the potassic and leucite rocks. Its mineralogy
indicates a strongly peralkaline original magma, also with a high grade of
titanium (TiO2).
The lamproitic
zones prove on the treatment tests to be the richest in diamonds than the
kimberlitic gaps, varying from 3.0 to 13.0 ct/m3, to 1.0 to 5.0 ct/m3 in the
gaps. Both zones are mineralized with diamond and must be exhaustively
researched and entirely mined after the C1
C2 and C3 thick clastics as well
as the base levels of Casa Branca Farm Formation.
2.8 SรO LUIS GAPS (SS3)
In the intemperized
occurrence of Sector 1, the kimberlites were initially regards as brownish
green microgaps formed by fragments of various sizes and shapes and minerals
from micaceous peridotitic nucleous collected in different level of the mantle
and crust.
The mineralogy of
these lamproitic masses indicates strongly peralkaline magma (defficient in
sodium and aluminium) and possibly with high grade of titanium (TiO2),
titaniferous phlogopite, amphibole, diopside microcrystals, titaniferous
magnetite, ilmenite and anatase. The main indicators of these diamondiferous
occurrences are prederite, wadeite (Zr2K4Si6O18), phlogopite rich in Ba
and titaniferous chromites.
More specific
studies of the origins of the diamonds in kimberlitic gaps and lamproitic zones
were not sufficiently performed through the mining company prioritary planning
which invested resources in order to immediately block immediate yield
secondary reserves.
2.9 STRUCTURAL ASPECTS
The area is marked
by a group of structural families involving longitudinal linings of 1st
and 2nd orders, subvertical faults, fractures, shear stains zones,
abrupt contacts, discordances, dykes and sills.
GEOLOGICAL MAP: SLML 02A
3
GEOTECHNICAL DRILLING OF LOW DEPTH
-
Linear
kilometers researched: 56.60;
-
Number
of holes performed: 257;
-
Number
of positive holes for diamond: 235;
-
Number
of negative holes: 22;
-
Depth
in meters researched: 995.6;
-
Variation
of thicknesses of C levels in meters: 0.10 2.35;
-
Variation
of thicknesses of sterile levels in meters: 1.00 5.00;
-
Occurrence
of gold: 00.
C levels proofs were analyzed
for diamond, gold and satellite minerals, by wash through 4 differential granulometric
sieves of +1.0 mm to 4.0 mm, and a five-liter bowl to verify gold. The
granulometric results were: Pebble - Thick (SG): > 200 mm; Medium Thick
(MG): 120 200 mm; Medium Medium (MM): 60 120 mm; Thin Medium (FM): 40
60 mm; Thin Thin (FF): 40 20 mm; Bowl concentrated (CB) < 20 mm.
4
GEOTECHNICAL DRILLING OF MEDIUM
DEPTH
This new phase
introduced in November-December 2005, FIG. 02 below, was specially adopted to
characterize the real thickness of the sedimentary cover of the area, which was
discussed many times due to the occurrence of false bedrocks, common at +- 4.00
8.00 m depth, considering the constant interruption of traditional holes at
this hardened clayish-sandy level without the textures and structures of the granitic-gneissic
basement known in the region. Five holes level tests were performed in W of Sector 1, with 89.00 m where the
first three holes were performed at L21 next to central camp, whose typical
profile revealed 3 levels of C gravels,
2 of them being at traditional depth level of 12.00 m, and a third one being at
base level, at 1.00 to 20.00 m.
FIG 02: SCHEMATIC GEOLOGICAL SECTION
HOLES WITH ROTATIVE PROBE MEDIUM DEPTH
๐Typical
in situ profile of deposits from
colluvial terraces in Sector 1 =
ท
Level A1 = brown low thickness sterile organic layer (+- 0.50 m); Level
B1 = reddish-yellow sandy-clayish medium thickness sterile layer of +- 1.00 m; Level C1 = limonitic-quartz aggregate with blocks and remnant
lateritic nodes, mineralized with diamond; Level
C2: reddish-white limonitic-quartz aggregate, gradually mineralized passing
to level C3; Level C3:
roselike-grey-smoked-white quartz gravel, involved in a mineralized
fundamental mass which was whitened and sandy-clayish, sometimes reddened; Level D = corresponding to hardened
granitic saprolite.
5
VOLUMETRICAL EVALUATION
Until January 2005 the evaluation was made with
panels with an apperture of 10x30m to
20x90m and +- 4.0 to +-10.0m depths.
The advances have been paralleled and with ascending
inclination of +- 05% for water drainage from more elevated cotes.
The objective inside the panels was the dismantling
of C levels producing a
representative volumetric sample of the deposit, which were processed in
primary and secondary jigs (Duplicated Fixed Plants PF).
Approximately 32.54 hectares were tested, +- 1.82%
of the surface of this Research License located in Sector 1.
In 2004, the test allowed to determine an average
grade of 1.53 ct/m3 in the deposits and 0.44 ct/m3 in the sedimentary package,
whose average result in 2001-2004 was 2.55 ct/m3. The integrated grades between
the researches and volumetric samples resulted in a final average grade of
1.6458 ct/m3 in the deposit and 0.19 ct/m3 in the sedimentary packages, which
currently represents the real anomaly of Sใo Luis deposit .
The possibility of adding the mineralized volume
since the confirmation of the medium geotechnical probing results is real,
because C3 gravel levels were
detected at +- 20m depth, beyond the confirmation of primary deposits
(saprolites from SS1, SS2 and SS3).
6
CHARACTERIZATION OF THE DEPOSITS
6.1 MORPHOLOGIES
Colluvial terraces,
transition zones, alluvia, shallow and deep paleocanals, Paleozoic Formations
which are slightly wavy as well as recent sediments, beyond primary
environments of difficult visual reach.
6.2 GENETIC MODEL
6.2.1 Primary deposits: Kimberlites and lamproites are primary magma
substances derived directly from the fusion of the base, which might have been
generated by immiscibility from a silicated super magma or by fractionated
crystalization. Studies of details on the evolution of pre-mining and mining
phase will help to define the advent of economical reserves of this level.
This magma which is
mineral and its mineral phases will be able to generate secondary economic
value among them: anatase, apatite, pyrochlore, monazite, which are minerals
crystalized during the kimberlites and lamproites genesis, and remain
disseminated in the magma that collected diamonds formed at the base and
transported them until the surface and/or near it where they were exposed to
the intemperic processes, eroded enriched the conjugated flood plains, also
contaminating the interlocks (e.g. Casa Branca Farm Formation base level from
Parecis Group) by mineralized magma injection through clefts, dykes and sills.
In these explosive
contact gaps (SS3) were created and
tested with success by the treatment tests, and revealed to be rich in olivine,
pyroxene, prico-ilmenite, piropo garnet, zircon, magnetite and apatite.
6.2.2 Secondary deposit Two subsystems were defined:
ุ Continental
Sedimentary Diamondiferous C gravels
deposits were formed in continental sedimentary environments, without sea
water;
ุ Hydathogenic
Sedimentary by Mineral Substitution - Diamondiferous C gravels deposits were formed in sedimentary environments as
consequence of circulation of non magmatic water in terrace environments,
transition zones, alluvions and paleocanals.
The mineralization
of the area is known thick clastics deposits which were defined as C1, C2, C3 and C4, according to the nature of its litological components. They are
extended, irregular, sub-plain levels of varied thicknesses, which enriched the
local environments.
These deposits were
supplied with pipes erosion, dykes, sills, kimberlite-lamproites and gaps from
Aripuanใ Province, which has already produced approximately 3 million carats of
diamonds.
6.3 PARAGENESIS
The frequent
mineral of the area and that will be
able to become an economic source are titanium ones: anatase (TiO2) and
ilmenite (Fe, Mg, Mn) TiO3.
Other minerals of
genetic importance are: piropo garnet, cyanite, chalcedony, zircon, hematite,
magnetite, turmalinite, roselike-saccharoidal-smoked-opaque-
hyaline-white quartz, amethyst quartz, silex, agate, carbonate, limonite,
goethite and oxides in general.
6.4 LITOLOGIES
Sedimentary covers, laterite-detritic covers,
unconsolidated sediments.
6.5 STRUCTURAL ASPECTS
They are
stratiphormical bodies formed inside of layers or paleocanals of porous
litologies (arenites and conglomerates), confined by impermeable (argillites)
or semi-impermeable (silts). They are noted crossed stratifications,
uncontinued structures, horizontal-subhorizontal lamination, convoluted beds,
subvertical structural-magnetic linings, ( S1,
S2, S3 and S4), fractures, dykes
and sills.
The most observed
transformations indicate hydrothermal-mineralogical alterations, specially in
the proximities of the structures convergence (sometimes denoting breccian aspects),
provenient from hydrostatic and/or
liostatic pressures of the involving pivots.
6.6 AGE
By the identified
characteristics, secondary hydathogenic deposits are, in the vast majority,
post-diagenetic from the Mesoproterozoic (1.700-1400 MY) and from Cambrian
(530-300 MY).
6.7 STRUCTURATION OF TERRACE TYPICAL PROFILE AND TRANSITION ZONE
SCALE
FORMATION CLIMATE
Humid tropical and
Dry tropical
ARGILMINERALS OF PREDOMINANT SATELLITES
Kaulinite, Fe and
Al hydratated oxides, anatase
Ilmenite, rare
smectites
Limonite and
neoformed goethite, hematite
Little magnetite
DESCRIPTION OF HORIZON
AR/AG, rich in organic material
AG/AR, VE/AM with noddles
AG/AR credit to goethite mottled zone AM-LAR/VE
Limonite-goethite/quartz aggregate with
diamonds of 0 > 4.0 mm (80%)
Quartz limonite-goethite aggregate with
diamonds of 0 > 4.0 mm (70%)
Freatic Surface (SF1)
AG, little AR, AM with oxidized spots (False
Bedrock)
AR, VE, easily breakable, rusting front, whose
cover is incorporated to the duricrust (?)
Fragmented level of F/M, BR/CZ/CREME gravel
SF2
Granitic saprolite with structures from the
preserved healthy rock, overlapped to the freatic with alkaline PH and neutral
and reducing Eh
Hard granitic rock
TABLE 04: TERRACE TYPICAL PROFILE AND
TRANSITION ZONE
7
CHARACTERISITICS OF MINERALIZATION
7.1 PRIMARY DEPOSITS
ุ Kimberlites SS1 Strongly intemperized nucleuses of +- 200m X+-
150m dimensions, covered by in situ thick
layer of sediments (+- 10m) and/or rejects
from former prospects with minerable grades. The
superficial treatment test at the SS1
cover revealed surprisingly result of grade of 1.50 ct/m3, as well as a very
expressive grade of piropo garnet, ilmenite, anatase, zircon, turmalinite. The
white spots are associated feldspar and kaulinite.
ุ Lamproites SS2 Nucleuses morphologically covered by thick
sediment layer (+- 5.0 m) and/or rejects from former prospects with minerable
grades, with dimensions of +- 150m X +- 100m. They generated semi-hardened
green soils with whitened semi-circular, centimetric, feldsphatic, ball clays
spots, containing expressive grade of piropo-almandine garnets, zircon,
ilmenite, anatase and chalcedony. The volumetric tests over the greenish masses
which were rich in garnets and titanium revealed a +- 2.50 m thickness from
where approximately 4,000.00 ct of diamonds were extracted, with grades varying
from 0.80 to 13.00 ct/m3.
ุ Gaps SS3 Lined expression bodies inside S2 families of structures, with expressive effect in N of Sector 1, with narrow dimensions of +- 20m X 80m, and average depth of 8.00m. It possesses xenolith in the sedimentary interlocks and the centimetrical dimension