PHOSPHATE MINING ON THE CHATHAM RISE

Transcription

1 PHOSPHATE MINING ON THE CHATHAM RISE ERIK SCHOUTE SENIOR ENGINEERING GEOLOGIST, BOSKALIS EMSAGG SEMINAR OPPORTUNITIES FOR EUROPEAN MINERAL RESOURCES BUNDESAMT FÜR SEESCHIFFART UND HYDROGRAPHIE (BSH), HAMBURG 26 FEBRUARY

2 INDEX INTRODUCTION CHARACTERISTICS OF DEPOSIT AND PHOSPHORITE NODULES LICENSE AREA AND RESEARCH HISTORY MINING PROCESS QUESTIONS 3

3 INTRODUCTION CHATHAM RISE STRETCHES FROM NZ SOUTH ISLAND TO JUST BEYOND CHATHAM ISLANDS 130 KM WIDE, 960 KM LONG, WATER DEPTHS M PHOSPHATE DEPOSITS ALONG 400 KM OF RISE PHOSPHORITE NODULES CONCENTRATED AT SEABED OR EMBEDDED IN GLAUCONITIC SILTY SAND AVERAGE PHOSPHORITE CONTENT OF NODULES IS 21.5% P 2 O 5 4

4 INTRODUCTION FERTILISER USE IN NZ ~3 M TONNES/YEAR PHOSPHORITE (OR: ROCK PHOSPHATE) AND SULPHURIC ACID ARE PRIMARY CONSTITUENTS OF SUPERPHOSPHATE (MAIN FERTILISER IN NZ) NZ IMPORTS ~100% OF ITS ROCK PHOSPHATE REQUIREMENTS (1 M TONNES/YEAR) FROM MOROCCO CHATHAM RISE IS NZ S ONLY SIGNIFICANT PHOSPHATE DEPOSIT 5

5 INTRODUCTION BENEFITS OF CHATHAM RISE ROCK PHOSPHATE: VERY LOW IN CADMIUM MUCH LOWER CARBON FOOTPRINT DIRECT APPLICATION OPTIONS (NO DIRECT NEED TO CONVERT TO SUPERPHOSPHATE) SECURITY OF SUPPLY CHEAPER SOURCE THAN MOROCCO REDUCED FOREIGN EXCHANGE RISKS IMPORT SUBSTITUTION AND EXPORTS 6

6 CHARACTERISTICS OF DEPOSIT PHOSPHORITE NODULES RANDOMLY DISTRIBUTED THROUGH LAYER OF VERY SILTY GLAUCONITIC SAND, MAXIMUM PROVEN THICKNESS 155 CM OVERLYING OLIGOCENE CHALK/OOZE PHOSPHORITE CONSTITUTES CA. 15% OF GLAUCONITIC SAND LAYER IN WHICH IT IS FOUND NODULE CONCENTRATION HIGHLY VARIABLE ON SCALE OF TENS OF METRES (0-350 KG/M 2 ) PHOSPHORITE RESOURCES ESTIMATED TO BE 25 M TONNES IN SITU IN WELL-RESEARCHED AREA OF 380 KM 2, ESTIMATED WORTH $5 B 7

7 CHARACTERISTICS OF DEPOSIT PHOSPHATE DEPOSITS FORMED LATE MIOCENE (7-12 M YEARS AGO) MIOCENE CHALK OVERLYING EARLY OLIGOCENE CHALK CHALK PEBBLES FORMED, UPTAKE OF PO 4 FROM MUD AND SEAWATER PHOSPHATISATION AND SURFICIAL FERRUGINISATION OF CHALK PEBBLES EROSION OF MIOCENE CHALK, FORMATION OF GLAUCONITE, GLAUCONISATION/SILIFICATION OF NODULE RIMS REDISTRIBUTION OF PHOSPHORITE BEARING SAND BY GOUGING ICEBERGS PRESENT REWORKING 8

8 CHARACTERISTICS OF NODULES CORE (I): WEAKLY PHOSPHATISED NANNO CHALK LAYER (II): INCREASINGLY MORE PHOSPHATISED CHALK ZONE RIM (III): GOETHITE ZONE (DARK BROWN) RIM (IV): COLLOPHANE ZONE (YELLOWISH) RIM (V): GLAUCONITE ZONE (GREENISH BLACK) 9

9 CHARACTERISTICS OF NODULES IRREGULAR SHAPES HEAVILY BURROWED AND BORED SIZE VARIES BETWEEN SAND (1-2 MM) AND COBBLE SIZE (>150 MM), VERY FEW >200 MM AVERAGE SIZE MM P 2 O 5 CONCENTRATIONS BETWEEN 21 AND 22.5% OTHER MAJOR CONSTITUENTS: SiO 2, CaO, Fe 2 O 3, F, Al 2 O 3, MgO HIGHEST CONCENTRATIONS IN 4-10 MM GRAIN SIZE FRACTION 10

10 CRP LICENSE AREA 11

11 CRP LICENSE AREA CRP LICENSE AREA MPL 50270, APPLIED AUGUST 2007, GRANTED FEBRUARY ,726 KM 2, WATER DEPTH M, KM EAST OF CHRISTCHURCH, NZ IN NZ TERRITORIAL WATERS CHATHAM ROCK PHOSPHATE LTD (CRP) PARTNERS WITH BOSKALIS EXTENSIVELY RESEARCHED IN RECENT YEARS 12

12 RESEARCH HISTORY PHOSPHORITE NODULES DISCOVERED BY NZ SCIENTISTS IN 1952 FIRST INVESTIGATED IN 1960/70 S EXTENSIVELY STUDIED IN 1978 AND 1981 JOINT BOSKALIS/CRP SITE INVESTIGATIONS IN 2011 AND 2012 FOUR SEPARATE CRUISES WITH R/V DORADO DISCOVERY, 50 DAYS SURVEY TIME MULTI-BEAM, SUB-BOTTOM PROFILER, SIDE SCAN SONAR, MAGNETOMETER, GRAB SAMPLING, VIBROCORING, MINI-CPT, BOX CORING, ROV SAMPLING, JET TESTING, VIDEO- AND PHOTOGRAPHY PROCESSING, INTERPRETATION AND REPORTING DONE IN NZ AND THE NETHERLANDS 13

13 R/V DORADO DISCOVERY 14

14 R/V DORADO DISCOVERY 15

15 GRAB SAMPLING 16

16 GRAB SAMPLING 17

17 GRAB SAMPLING 18

18 VIBROCORING 19

19 VIBROCORING 20

20 VIBROCORING 21

21 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 22

22 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 23

23 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 24

24 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 25

25 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 26

26 ROV ZEUS (BATHY, VIDEO, SAMPLING, JET TESTING) 27

27 DETAILED MULTI-BEAM BATHYMETRY 28

28 SIDE SCAN SONAR 29

29 SIDE SCAN SONAR 30

30 SIDE SCAN SONAR 31

31 FRACTION ANALYSIS 32

32 FRACTION ANALYSIS 33

33 MINING CONSIDERATIONS PRIMARY FACTORS INFLUENCING MINING PLAN: VARIABLE WATER DEPTH AND MORPHOLOGY VARIABLE LAYER THICKNESS AND COMPOSITION OF DEPOSIT VARIABLE RESOURCE CONCENTRATION IMPACT ON BENTHIC AND PELAGIC ENVIRONMENT ECONOMICS (CAPITAL AND OPERATIONS EXPENSES, EXPECTED (WORLD AND LOCAL) MARKET FOR PHOSPHORITE) GOAL: MINING OF 1.5 M TONNES/YEAR ROCK PHOSPHATE, TARGET START DATE JANUARY 2015 SOLUTION: MODIFIED TRAILING SUCTION HOPPER DREDGER 34

34 MINING CONSIDERATIONS 35

35 FLEXIBLE DREDGING SYSTEM 36

36 FLEXIBLE DREDGING SYSTEM TOP VIEW SIDE VIEW 37

37 UNLOADING OPTIONS (WET/DRY) 38

38 PROPOSED MINING CYCLE DREDGING FOR SEVERAL DAYS, RESULTING IN 50,000 TONNES OF NODULES RECOVERY AND STEAMING TO PORT, CA. 1 DAY UNLOADING (WET/DRY OPTION, DECISION TO BE MADE) AND PREPARING FOR MINING TRIP, CA. 1 DAY STEAMING BACK TO SITE FOR NEXT MINING TRIP, CA. 1 DAY 39

39 QUESTIONS? 40