New Discovery of Bauxite, Central Borneo-Indonesia

NEW DISCOVERY OF

RESIDUAL LATERITIC BAUXITE DEPOSIT

PARENGGEAN-CENTRAL KALIMANTAN

By

Hizian Darwin

2005

NEW DISCOVERY OF RESIDUAL LATERITIC BAUXITE DEPOSIT

PARENGGEAN-CENTRAL KALIMANTAN

By

Hizian Darwin Geologist

2005

Bauxitethe Dutaken severaanothe1977, iAntam Surprisby bothKalimanear thThe bametamresiduaforminW andlateriticthick inAl2O3 Based geologapproxthan 10distribuconfideobservshould over th

e in Indonetch geologover by Pl localities er location in a bauxit.

singly, signh the Dutcntan regiohe Parenggauxite is morphics anal lateritic.g low‐lyingd NE‐SW dc varies fron averagedup to 56.9

on the reical resourximately 1,0% iron coution of rence levelation is rbe undert

he entire p

esia was figists. ProduPT. Aneka of bauxitewas previote Contract

ificant grach and prevon by authgean sub‐dassociatednd probabl. The laterg hills of ddirection atom 1.0 to d. Several 9% Al2O3

stricted darce of 20.0,000 hectaontent. Intresidual las of econrecommentaken in coroperty.

LATERITIC

rst discoveuction of tTambang e prospectously discot of Work

de of latervious foreior (geologdistrict, Kod with chey volcanic ritic formsome‐shapet elevation4.5 m parof channewith low to

ata obtain0 million toares gradinerpretive sateritic prnomic poteded. Recoonjunction

C BAUXITE‐CEBY Hizian Da

SUMM

ered on Bihe Bintan (ANTAM) t over Indoovered by Aarea. Toda

ritic bauxitgn compangist) in earotawaringinemically drocks of Ms a layeringed structun betweenrtly mantleel samples o moderat

ed to dateons (50% rng 50% Al2satellite imrobably exential of bonnaissanc with test

ENTRAL KALIMrwin (2005)

MARY

ntan Islanddeposit bein 1968 uonesia werALCOA in Tay, the Tay

te, locatedny of Alcoaly 2005. Thn Timur Dideeply weMatan comg of blankres with mn 15 and 6ed on top bcollected

te silica and

e, the areaecovery) w2O3; 1.34%mage undextends to bauxite dece‐scale mpitting, co

MANTAN

d in 1925 aegan in 193until the pre noted bTayan‐wesyan bauxit

d on the vira, was recehe new baistrict, Cenathered fplex of upket‐like anmajor axis l60 m abovby thin dafrom quad iron cont

a is roughwashed ba%‐11% SiOrtaken on all of di

eposits onmapping anosteaning a

and other 35 and thepresent timby the Dutt Kalimante is being

rgin and uently discoauxite discntral Kalimrom Earlyper Triassid massivelying in an ve sea levrk brown srry returntents.

ly estimatuxite cont

O2 (5% avethe properections. Tn the propnd geocheand or mec

Riau Islanence it hasme. In addtch workertan during explored b

ntargetedvered in Covery is loantan proy Triassic c in age fo chunks inapproximel. Thicknesoil up to ed assay >

ed containained in aeraged) anerty displayTo elevateperty, a fuemical samchanized d

ds, by s been dition, rs and 1969‐by PT.

areas entral ocated vince. Pinoh rming n part ate E‐ess of 2.0 m > 50%

ning a rea of d less ys the e the urther mpling drilling

Report area

FIGURE: 1. REGIONAL LOCATION OF REPORT AREA (MapMart-Intra Search, 2006)

LIST OF CONTENTS

SUMMARY

Preface

INTRODUCTION

• Location and Access • Physiography and Vegetation

HISTORY OF BAUXITE EXPLORATION REGIONAL GEOLOGY LOCAL GEOLOGY SAMPLING and ANALYSIS LATERITIC BAUXITE MINERALIZATION GEOCHEMISTRY POTENTIAL RESOURCE (GEOLOGICAL) CONCLUSIONS AND RECOMMENDATIONS REFERENCES

FIGURE

1. REGIONAL LOCATION OF REPORT AREA 2. FORMER CONCESSION C.O.W OF ALCOA Company 3. SIMPLIFIED GEOLOGIC MAP OF MENTAYA‐TUALAN RIVERS, CENTRAL KALIMANTAN

(Modified from GSI, 1995)

TABLE

1. RESULT OF SAMPLES ANALYSIS

PHOTO

1. General morphology of the property 2. View profile of lateritic at quarry 3. Lateritic profile on metamorphic bedrock 4. Massive block of bauxite 5. Larger chunks with erratic cavity 6. Cemented Oolitic-pisolitic bauxite 7. Profile of lateritic showing the thickness

APPENDIX

Analytical result of samples

NEW DISCOVERY OF LATERITIC BAUXITE-CENTRAL KALIMANTAN by Hizian Darwin (2005)

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PREFACE Bauxite is the primary ore of aluminum and is a naturally occurring, heterogeneous mineral composed primarily of one or more aluminum hydroxide minerals plus various mixtures of silica, iron oxide, titanium, aluminosilicate, and other impurities in minor or trace amounts (P.K. Banerji, 1982). Bauxite is a weathering product of aluminous rock that results from intense leaching in tropical and subtropical areas, a process called laterization (Lamb, C, 2005). It has a wide range of common uses and approximately 85% of the world bauxite production is processed into aluminum. The principal aluminum hydroxide minerals found in varying proportions with bauxites are gibbsite and the polymorphs boehmite and diaspore. Bauxites are typically classified according to their intended commercial application: abrasive, cement, chemical, metallurgical, refractory, etc. (USGS, 2007). This quickly growing demand has given rise to a continuing search for bauxite all over the world. Guinea is the first ranking of world’s bauxite reserves and resources followed by Australia, Brazil, Jamaica and China (Stockill, B, 2006). In Indonesia, PT. Aneka Tambang is a single producer of bauxite since 1968 in the Island of Bintan, Riau of Islands‐Sumatra.

INTRODUCTION The presence of bauxite in Indonesia was first discovered on Bintan Island in 1925, by the Dutch geologists and it has initially been mined in 1935 (Van Bemmelen, 1949). Several localities of bauxite in Indonesia were thought by the Dutch workers to have potential in West and Southwest of Kalimantan. In 1975, ALCOA had discovered large and low grade bauxite in Tayan area, West Kalimantan province. The Tayan deposit is currently being explored by PT. ANTAM Tbk. (Van Leeuwen, T.M, 1993). As known, Central Kalimantan was not a target area for bauxite exploration both by the Dutch and previous aluminum company (ALCOA) and they were concentrated in Eastern Sumatra, Riau Islands, Banka‐Belitung, West and South Kalimantan, Central Java, Sumba, Buton Island, Sula Islands, Aru Island and Southern East of Irian Jaya (Figure: 2). Surprisingly, significant grade of bauxite deposit was recently discovered by author in early 2005 in Central Kalimantan who initially investigated for lateritic iron on Kotawaringin Timur region. The new bauxite discovery is located near the Parenggean village, Kotawaringin Timur District.

FIGURE: 2. FORMER CONCESSION OF ALCOA BAUXITE C.o.W (approx. 500,000 km2)

Report areaReport area

Bauxite C.o.W

(Modified from Van Leeuwen, 1993)


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The main aim of this report, therefore, was to provide significant geological information in relation to the discovery of bauxite in Central Kalimantan. A detail exploration work is recommended to add more geological information especially in mineral resources in Indonesia. Be expected that the results would obtain significant information to evaluate the potential profitability of developing or expanding mining operations. Location and Access The new bauxite discovery is located in Parenggean subdistrict (Kecamatan), Kotawaringin Timur District, Central Kalimantan Province and lies at 01⁰59’56.5” S (latitude) and 112⁰47’36.8” E (Longitude). Parenggean is approximately 140 km west of Palangka Raya and accessible by paved all‐weather road from Palangka Raya town to Palantaran village and thence finally about 30 km of dirt and gravel roads leading to property area. Palangka Raya, the district capital of Central Kalimantan province has daily air service from Jakarta on the regional commercial carriers, Batavia and Sriwijaya Airlines. The total driving time is about 5 hours. Physiography and Vegetation The concession topography is characterized by flat to gently undulating with elevation range 15 m and 66 m above sea level. Most hills, however, are between 30

and 60 m high, with local topography relief typically averaging 25 m above sea level. The hills are considered remnants of an erosion surface. Valleys are typically swampy and small lakes (such Danau Rasau and Danau Sirai) further on the south, while hilltops tend to be clear. Photo: 1. Gently rolling terrain

Primary forest has been largely cleared from the area (Photo: 1 and 2). Small portion of the area is now covered with rubber trees and palm plantation belongs to local natives. Large areas‐especially those underlain by bauxite are covered with bush and grass. The eastern sides of area are incised by Tualan River, a tributary of Mentaya main River (approx. 40 m wide) flowing from NNE to SSW in direction.


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Photo: 2. View profile of lateritic cut by backhoe (unbottomed) for road construction Some places, the bauxitic laterite are being excavated for construction of the rural access and palm farm roads (Photo: 2).

HISTORY OF BAUXITE EXPLORATION

The presence of bauxite in Indonesia was first noted in 1925 on Bintan Island and the bauxite deposits were placed into production in the 1935 by the Dutch. Other bauxite locations have been found such as Kundur, Batam , Bangka and Belitung but they are not of commercial value at the time. West and southwest of Kalimantan were interpreted to be present considering the geological condition be expected similar to bauxite deposit in Bintan, however, no investigation had been carried out yet (Van Bemmelen, 1949). In 1969, ALCOA was a granted a bauxite C.o.W area covering a total of approximately 500,000 km² over the Indonesia Archipelago (Figure: 4). In 1971, the original C.o.W area had been reduced to about 19,000 km² and further reduced to 1,300 km² in West Kalimantan. In 1974, the feasibility study had been undertaken for Tayan area which contains the largest single deposit of 270 Mt. In 1977, however, ALCOA had decided to relinquish the C.o.W area reportedly due to financing and marketing problem (Van Leeuwen, 1993). Today, the Tayan prospect is currently being explored by PT. Antam and be expected the mining operation would be shortly commenced.

REGIONAL GEOLOGY

Indonesia is located at the convergence of three lithospheric plates, and hence its geology is influenced numerous subduction zones. Kalimantan in underlain largely by Paleozoic to Mesozoic aged sediments and volcanics intruded by Cretaceous granitoid rocks, and this represents an amalgamation of perhaps several Permo‐Cretaceous volcano‐plutonic arcs (Van Bemmelen, 1949; Katili, 1975; Hamilton, 1979). Late Cretaceous to early Tertiary marine and continental strata was deposited along the northern shelf margin of the Sundaland and was subsequently deformed in


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the Eocene in which the Sundaland was a passive continental margin at the time (Carlile, J. A and Mitchell, A.H.G, 1993). The youngest eruptive rocks with related to basalt flows are widespread in Kalimantan during Late Miocene to Quaternary and they unconformably overly the flysch sediments (Halligan, 1984).

LOCAL GEOLOGY

As geological map published by GSI (E.S. Nila et al, 1995) that the area is dominantly underlain by alluvial deposits and sedimentary rock of Dahor Formation (Figure: 3). The Dahor consists of fine to coarse quartz sandstone, conglomerate and coal seam or lignite and is presumably middle Pliocene to Pleistocene in age. The area is poor in outcrops and largely covered by lateritic and clay associated with low relief morphology. The oldest rocks exposed in the area are Pinoh metamorphic rocks composed of phyllite, schist, quartzite and gneiss of Triassic in age (Van Bemmelen, 1949). Photo: 3. Lateritic profile (metamorphic origin)

Triassic volcanic rocks occupy to north of the area at upstream of Tualan River. The metamorphic rocks are cropped out approximately 20 km north of the area where few local natives are panning for lateritized gold. The lateritic is developed on metamorphic bedrock with a 2‐3 m thick and it is overlain by about 0.50 m light brown soil (Photo: 3).

LATERITIC BAUXITE MINERALIZATION Laterites result from dominantly chemical (aided by mechanical) weathering at and

near surface temperatures and pressures in tropical regions. Different stages of the lateritization process, involving both the formation and destruction of laterites, are seen today in the tropical belt that forms about 15 per cent of the Earth's land surface. Photo: 4. Massive block of bauxite at Parenggean

01 45’00”E

02 00’00”E

112

45’0

0”

E

113

00’0

0”

E

Pinoh Metamorphics (Permian-Triassic)Pinoh Metamorphics (Permian-Triassic)

Volcanic rocks (Triassic)Volcanic rocks (Triassic)

Sepauk Tonalite (Cretaceous)Sepauk Tonalite (Cretaceous)

Sintang Intrusive rocks (Eocene-Miocene)Sintang Intrusive rocks (Eocene-Miocene)

Dahor Formation (Plio-Pleistocene)Dahor Formation (Plio-Pleistocene)

Alluvium (quaternary)Alluvium (quaternary)

LEGEND

0 10km

Stream

Fault

SIMPLIFIED GEOLOGIC MAP

MANTAYA-TUALAN RIVERS

CENTRAL KALIMANTAN

SIMPLIFIED GEOLOGIC MAP

MANTAYA-TUALAN RIVERS

CENTRAL KALIMANTAN

FIGURE: 3FIGURE: 3

S.Tuala

n

S.Mantaya

(modified from GSI, 1995)(modified from GSI, 1995)

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Report area

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This includes a large part of Africa from Niger to Angola, the Americas from Mexico to Brazil, Southeast Asia from India to Indonesia, and the northern half of Australia (P.K. Banerji, 1982). The available data to date indicates that the bauxite deposits occur a layering of blanket‐like and massive chunks in part (See Photo: 4 and 5). The bauxite tends to form the upper and middle levels of the low‐lying hills form dome‐shaped structures with their major axis lying in an approximate E‐W to NE‐SW orientation.

The individual deposits are extremely heterogeneous and vary from 1000 to 2000 meters length or more. The thickness of bauxite varies from 1.0 to more than 4.5 m (see Photo: 5) partially mantled on top by dark brown soil ranging in thickness between 0 and 3.0 m. Photo: 5. Larger chunks with erratic cavity bauxitic laterite.

The thickness of laterite profile is determined by the balances between the rate of chemical weathering at the base of the profile and physical removal of the top of the profile by erosion (M. Elias 1996). This residual deposits form by a peneplanation of the host rocks containing iron, olivine, pyroxene, feldspar or feldspathoid under the tropical conditions, and by formation of a deep leaching zone in the forming peneplane. This leaching zone is closely related with tectonic stability, however, in forming of the residual deposits, host rock, climate, topographic features, and geomorphologic evolution have significant role ((TÜFEKÇİ, K., 1991).

The bauxitic sand (oolitic) to gravel (pisolitic) particles is dominant in the area in which they are locally cemented mainly from the middle section to downward. The cemented gravels are formed when iron is precipitated by groundwater fluctuations and thereby accumulates as nodules and pisoliths when the water evaporates (Hyland, S. 2007). Photo: 6. Cemented Oolitic‐pisolitic bauxite exposed at Parenggean

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Laterites are very heterogeneous materials, and their fabric elements vary from one place to another. The relationship between the appearance of new minerals and the formation of voids is a key factor that needs to be established. The structures and textures now seen in laterites may have formed at different periods and through different processes (P.K. Banerji, 1982).

This lateritic is inferred to be more than 4.0 m in thickness (Photo: 7) and it is characterized by the development deep chemical weathering or mature in geomorphologic evolution represented generally by high concentrations of gibbsite and or aluminum phosphate compare to immature ones are poor in these minerals (Costa, M. L, 1997).

Photo: 7. Thickness of bauxite (a man standing scale) at quarry The most common aluminum‐bearing minerals in bauxite are gibbsite boehmite and diaspore (MacKenzie, G. Jr. et al., 1958). The best bauxites occur in very old reliefs, generally Tertiary (R. Maignien, 1966).

SAMPLING and ANALYSIS

Limited vertically channel sampling was carried out from two separate locations with a distance of about 1.5 km each other. The samples were collected from top to bottom of pit as a composite sample. Two types of samples were analyzed consisting of unwashed and washed samples. The latter samples were sieved using 4 mm screen and then dried prior to sending to laboratory. The samples were sent to two different laboratories of SDM (Bandung) and PT. Intertek Utama Services (Jakarta) to get a better result for comparative.

GEOCHEMISTRY A reconnaissance channel sampling was conducted at several locations to be representative of the material exposed at surface. Assay results from reconnaissance sampling are tabulated in table 1.


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TABLE: 1.

Sample No SiO2 (%) Al2O3 (%) Fe2O3 (%) TiO2 (%) H2O (%) PGR‐002R 1.74 52.67 9.02 0.44 1.09 PGR‐003R 1.34 52.70 11.36 0.74 0.95 LTR‐003‐D* 11.16 51.31 13.85 1.74 2.06 PGR‐004** 5.92 56.99 8.65 0.94 0.50 Notes: * Sample was not sieved included clay fraction ** Sample was washed and sieved by 4mm screen prior to crushing

POTENTIAL RESOURCE (GEOLOGICAL)

Based on the restricted data obtained to date, the area is estimated containing a geological resources of 20.0 million tons washed bauxite contained in area of approximately 1,000 hectares grading 50% Al2O3; 1.34%‐11% SiO2 (5% in averaged) and <10% Fe2O3 with recovery factor of approximately 50% is roughly estimated. Interpretive satellite imagery undertaken on the property displays potential bauxite mineralization may extend to west, south and probably north of the area.

CONCLUSIONS AND RECOMMENDATIONS

Although limited works and results obtained to date are insufficient to demonstrate, potential exists to find bauxite deposit within the area. Preliminary result of samples analyzed imply a similarity geochemistry of bauxite deposits in Bintan Island containing a high‐grade alumina (>50% Al2O3) and low silica content (< 5% SiO2). To elevate the confidence levels of economic potential of bauxite deposits on the property, a further observation is recommended. Reconnaissance‐scale mapping and geochemical sampling should be undertaken in conjunction with test pitting, costeaning and or mechanized drilling over the entire property.

Title : NEW DISCOVERY OF RESIDUAL LATERITIC BAUXITE DEPOSIT PARENGGEAN‐CENTRAL KALIMANTAN Author : Hizian Darwin Position : Geological Consultant (Geologist) Company : PT. DASAR MANGGALA Address : Kopo Permai II‐Blok 35AD, No. 18, Bandung 40227

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REFERENCES

Carlile , J. C and Mitchell A.H.G, 1993. Magmatic arcs and associated gold and copper mineralization in Indonesia.

Costa, M. L, 1997. Lateritization as a Major process of Ore Deposit Formation in the Amazon Region. Geosciences Center, Federal University of Para, Brazil.

Hamilton, W.B., 1979. Tectonic of the Indonesian region. Prof. Paper 1078. US. Geol. Surv., Washington, DC.

Halligan, 1984. Geology of the Central area, Central Kalimantan

Hains, D. H, 2005. Report on Port Loko Bauxite Deposit in Sierra Leone Hyland, S., 2007. Bauxite Resources in Darling Range, Western Australia Katili, J. A., 1975. Volcanism and Plate tectonics in the Indonesian Islands Arc . Lamb, C, 2005. Bauxite. Earlham Physical Geology College MacKenzie, G., Jr., Tracey, J. I., Jr., and Ellis, M. W., 1958, Geology of the Arkansas

bauxite region: U. S. Geological Survey Nila E.S, et al, 1995. Geological map of the Palangkaraya Quadrangle, Kalimantan P.K. Banerji, 1982. LATERITIZATION PROCESSES: CHALLENGES AND OPPORTUNITES. R. Maignien, 1966. Review of research on latérites, UNESCO. Stockill, B., 2006. Bauxite‐Facts Natural Resources, Mines and Water, Queensland‐

Government. TÜFEKÇï, K, 1991. Economic Potential of Residual Deposits in Peneplanated Areas in

Turkey, Mineral Res. Expl, 112, 39‐46, 1991 USGS, 2007. Bauxite and Alumina Statistics and Information Van Bemmelen, 1949. The Geology of Indonesia‐Volume II, Economic Geology Van Leeuwen, T. M, 1993. 25 Years of Mineral Exploration and Discovery in

Indonesia.

APPENDIX

INTERTEK CALEB BRETT(PT. INTERTEK UTAMA SERVICES)

XRF analysis determines total element concentrations which are reported as oxides

Our Ref: 065126Your Ref: 26/12/06 IDENT Al2O3 CaO Cr2O3 Fe2O3 K2O LOI MgO MnO Na2O P2O5 SiO2 TiO2UNITS % % % % % % % % % % % %DET.LIM 0.01 0.01 0.01 0.01 0.01 0.1 0.01 0.01 0.01 0.01 0.01 0.01SCHEME XR80 XR80 XR80 XR80 XR80 XR80 XR80 XR80 XR80 XR80 XR80 XR80SRK1 51.2 0.01 0.01 12.4 0.02 26.3 0.24 0.06 <0.01 0.03 7.31 1.44SRK2 51.9 0.01 0.01 16.2 0.01 27.5 0.24 0.05 <0.01 0.03 2.01 1.77

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New Discovery of Bauxite, Central Borneo-Indonesia