Mineral Economics and Mining Geology Flashcards
1
Q
It has a hole diameter of 122.6 mm and core diameter of 85 mm
A
PQ
2
Q
It has a hole diameter of 48 mm and core diameter of 27 mm
A
AQ
3
Q
It has a hole diameter of 75.7 mm and core diameter of 47.6 mm
A
NQ
4
Q
A map that can either be a topographic map or an aerial photograph of the area which orients the map user to the location of the details within the geologic map.
A
Base Map
5
Q
What is the differences between large- and small-scale maps?
A
Large-scale - high ratio (ex. 1:1,000)
Small-scale - small ratio (ex. 1:1,000,000)
6
Q
A type of drill that utilizes a helical drill that digs through the material and acts as a conveyor to remove the material.
A
Auger Drill
7
Q
A type of drill that utilizes a helical drill that digs through the material and acts as a conveyor to remove the material.
A
Auger Drill
8
Q
A method of drilling that uses a diamond drill bit used to cut through and recover core samples
A
Diamond-Core
9
Q
A type of drilling that uses a dual-walled rod, which means it has an inner rod where the core cuttings pass through to be transported out.
A
Reverse-Circulation
10
Q
A drilling method which employs the use of sharp, rotating drill bits to cut through the material.
A
Hydraulic Rotary
11
Q
A method of shallow, lateral excavation that is usually best done with an overburden of less than 3 m.
A
Trenching
12
Q
A method of vertically excavating from the surface or from one level to another in an underground mine.
A
Winzing
13
Q
An RQD value of 60% is labelled as:
a. Poor
b. Fair
c. Good
d. Excellent
A
Fair
14
Q
An RQD value of 40% is labelled as:
a. Poor
b. Fair
c. Good
d. Excellent
A
Poor
15
Q
An RQD value of 85% is labelled as:
a. Poor
b. Fair
c. Good
d. Excellent
A
Good
16
Q
What core sizes are not allowed for RQD?
A
AQ and BQ
17
Q
A mechanical, surface mining method that involves creating a deep, wide pit, that’s supported by benches, for excavating shallow metal or nonmetal deposits.
A
Open Pit
18
Q
A mechanical, surface mining method that involves creating a deep, wide pit, that’s supported by benches, for excavating shallow metal or nonmetal deposits.
A
Open Pit
19
Q
A mechanical surface mining for dimension stones or aggregates which involves slicing large, vertical benches of the commodity.
A
Quarrying
20
Q
A mechanical, surface mining often interchangeable with “strip mining” and is similar to ope-pit mining but for a more shallower deposits. Common for coal and nickel laterite deposits.
A
Open Cast
21
Q
A mining method that involves stripping by following a specific contour of the deposits.
A
Contour
22
Q
A mechanical surface mining method commonly used for extracting commodities from seams.
A
Auger
23
Q
A non-mechanical method that utilizes manpower to sieve through the alluvial deposits for the ore.
A
Panning
24
Q
An aqueous, surface mining method that utilizes the power of jet streams of water to break the orebody and retrieve the ore. It has been banned in some countries.
A
Hydraulicking
25
An aqueous surface mining method that extracts minerals along streams where the minerals have accumulated as unconsolidated alluvial deposits.
Placer
26
An aqueous surface mining that involves extracting minerals contained in sediments partly underwater or in shallow bodies of water using an excavator.
Dredging
27
An aqueous surface mining method that extracts minerals in situ by utilizing different solutions which can leach them out. Linked with uranium deposits.
In-situ leaching
28
An unsupported underground mining method that is one of the oldest methods, and is done by developing a grid, which are then used to self-support the system. For flat lying deposits.
Room and Pillar
29
An unsupported underground mining method that is similar to Room and Pillar having only the shape of the pillars left. Irregular spaces.
Stope and Pillar
30
An unsupported underground mining method where the ore is excavated horizontally and is progressively excavated upwards, while being extracted at the bottom through funnels.
Shrinking Stoping
31
An unsupported mining method that is done by creating patterned drillings through a steeply dipping ore body through stopes in sublevels and then blasted before collecting the broken ore.
Sublevel Stoping
32
An underground mining method in which the ore and surrounding waste rock are both blasted and allowed to cave as ore is extracted from lower sublevels. Commonly done in steeply dipping ore bodies and the operation is done in the footwall.
Sublevel Caving
33
A supported underground mining method where the ore is mined horizontally in levels progressing upwards and backfilled once the ore has been extracted and serves as the new platform for the upper level.
Cut and Fill Stoping
34
True or False. Waste rock is efficiently used as a backfill material in many mining methods.
True
35
An old, supported underground mining method that heavily relies on square set-timbering as support system for every square set of excavated parts of the ore body, which is eventually backfilled after one section is mined out.
Square Set Stoping
36
A caving underground mining of flat-lying, and relatively thin, tabular deposits, usually coal, where shearing machineries are used to extract coal as it travels back and forth across its coal face. As the shearers cross the coalface, moveable roof supports are installed to support the overlying strata
Longwall stoping
37
A caving underground method for hard rock that involves mining the ore body from under and allowing it to collapse on its own. It is considered as an underground analog of open-pit mining. The method utilizes funnels where the orebody is lead to for extraction.
Block Caving
38
Define Upstream, Midstream, and Downstream Industries
Upstream: Identification, Extraction, and Production of goods
Midstream: Transportation and Storage services
Downstream: Processing, Post-production, Bringing to consumers
39
Gross vs Net Income
Gross - Total income without accounting tax and royalties
Net - Total income accounting tax and royalties
40
A tax imposed by the government for the income generated the generally amounts to ____% of the net income.
Income tax; 32%
41
A tax imposed by the government for the production, sales and/or consumption generated that amounts to ___% of the gross sales.
Excise Tax; 4%
42
How many grams in 1 oz?
28.35 g
43
A mining company has two stockpiles of Nickel ore: A: 9000MT with 1.5% Nickel and B: 7000MT with 2.4% Nickel. Determine the total tonnage of ore needed if the buyer requires a minimum grade of 2.0% Nickel.
* Since Stockpile A did not meet the minimum requirements, "x" MT of it is used to dilute Stockpile B with to lower total grade and meet the minimum grade requirement.
(7000 × 0.024) + (x × 0.015) = ((x+7000)×0.02)
x = 5600 MT
Tonnage = 7000 MT (from B) + 5600 MT (from A)
Tonnage = 12600 MT at 2.0% Ni
44
Minimum amount of mineral deposits for it to be considered world class deposits
a. Gold
b. Silver
C. Copper
d. Zinc
e. Lead
a. Gold - 100 MT
b. Silver - 2,400 MT
C. Copper - 2,000,000 MT
d. Zinc - 1,700,000 MT
e. Lead - 1,000,000 MT
45
A group made up of representatives from various organizations that aim to standardize the code for reporting exploration, mineral resource and mineral reserve results. They are responsible for drafting JORC and PMRC.
Committee for Mineral Reserves International Reporting Standards (CRIRSCO)
46
A geometric resource estimation method that utilizes the area of a certain drillhole to estimate the grade for a specific depth and point.
Area of Influence method
47
A geometric resource estimation method best used for uneven drillhole spacing and estimates the area of Influence by extending it halfway through the distance from its neighboring drillholes, resulting in varying areas.
Polygon Method
48
Area of a rhombus
A = h((a+b)/2)
49
A geometric resource estimation method based on elevation of the area. It utilizes the area of a rhombus.
Contour Method
50
A geometric resource estimation method used for elongated, irregularly-shaped deposits, and is applicable when the vertical distance is greater than the horizontal distance of each drill hole.
Cross-Section Method
51
A geostatistical resource estimstion method that assigns a value to a block based on nearest available data to the centroid of a block.
Nearest Neighbor Method
52
A geostatistical resource estimation method based on the empirical observation that the bearing of each sample is proportional to an inverse power of the distance from the location of the estimated point to the samples.
Inverse Distance Weighting Method
53
A geostatistical resource estimation method that applies the concepts of ellipsoid search radius derived from variograms plotted from data acquired from samples.
Ordinary Kriging Method
54
The following are Porphyry Cu-Au deposits except:
a. Taganito Mining Corp.
b. Dipidio Mine
c. Padcal Mine
d. Philex Mining Corp.
Taganito Mining Corp (Nickel)
55
Which of the following employs cut and fill stoping mining method?
a. Dipidio Mine
b. Apex Mining Co. Inc.
c. Co-O Mine
d. Lepanto Consolidated Mining Company
Apex Mining Co. Inc. (Cut and Fill) and Lepanto Consolidated Mining Company (Shrinkage Stoping and Cut and Fill)
56
Which of the following employs block caving mining method?
a. Co-O Mine
b. Silangan Mindanao Mining Co.
c. Philex Mining Corporation
d. Oceana Gold
Answer: Philex Mining Corporation
a. Co-O Mine (Shrinkage, Stope and Pillar)
b. Silangan Mindanao Mining Co. (Sublevel Caving)
d. Oceana Gold (Open-pit, Shrinkage)
57
A horizontal opening driven from the surface which give access to the orebody. It is not open at both ends unlike tunnels.
Adit
58
An alloy of mercury and other metals
Amalgam
59
Entries at the back of the panel where the extraction begins and provide continuity in mine ventilation.
a. Bulkhead
b. Bleeder entries
c. Breakthrough
d. Breast
Answer: **Bleeder entries**
***Bulkhead*** - A timber or concrete dam to _hold air, tailings or water in place_.
***Breakthrough*** - A passage that allows the ventilating current to _pass from one room to another_.
***Breast*** - The vertical end _surface of a working heading_.
60
A timber or concrete dam to hold air, tailings or water in place.
a. Bulkhead
b. Bleeder entries
c. Breakthrough
d. Breast
Answer: **Bulkhead**
***Bleeder entries*** - Entries at the back of the panel _where the extraction begins_ and provide continuity in mine ventilation.
***Breakthrough*** - A passage that allows the ventilating current to _pass from one room to another_.
***Breast*** - The vertical end _surface of a working heading_.
61
A passage that allows the ventilating current to pass from one room to another
a. Bulkhead
b. Bleeder entries
c. Breakthrough
d. Breast
Answer: **Breakthrough**
***Bleeder entries*** - Entries at the back of the panel _where the extraction begins_ and provide continuity in mine ventilation.
***Bulkhead*** - A timber or concrete dam to _hold air, tailings or water in place_.
***Breast*** - The vertical end _surface of a working heading_.
62
The vertical end surface of a working heading.
a. Bulkhead
b. Bleeder entries
c. Breakthrough
d. Breast
Answer: **Breast**
***Bleeder entries*** - Entries at the back of the panel _where the extraction begins_ and provide continuity in mine ventilation.
***Bulkhead*** - A timber or concrete dam to _hold air, tailings or water in place_.
***Breakthrough*** - A passage that allows the ventilating current to _pass from one room to another_.
63
a non-explosive blasting system. The ultimate solution for build-up & blockage issues in storage vessels, pre-heaters, coolers, inlet chambers, silos, raw feed mills, riser ducts, rotary kilns, and other high-heat process equipment. It utilizes the expansion properties of liquid carbon dioxide.
Cardox
64
A permitted device used in some English coal mines using a powder charge composed of ammonium chloride and sodium nitrate.
Hydrox
65
A baked mixture of caustic soda and lime, used in the container or regenerator of self-contained mine rescue or oxygen breathing apparatus to absorb inhaled CO2.
Cardoxide
66
A hydraulically actuated road support.
a. Chocks
b. Collar
c. Girt
d. Pack
Chocks
67
An artificial support system made from shaped rocks, concrete or pumice blocks.
a. Chocks
b. Collar
c. Girt
d. Pack
Pack
68
Is the caved area produced from the collapse of the mined out portion of the deposits.
a. Easer
b. Mole
c. Stull
d. Gob
Gob
69
A process for mining sulfur in which superheated water is forced into the sulfur deposit to melt it.
Frasch Process
70
Weight of waste to be extracted to mine one unit weight of ore (waste to ore ratio)
Stripping Ratio
71
As pit dimensions get bigger, the stripping ratio exponentially increases also. When the stripping ratio reaches a threshold where increasing pit size is no longer economic, a term called:
Maximum stripping ratio
72
refers to dirt and rock piled alongside a haulage road or along the edge of a dump point
Berm
73
Slopes are steepened in its final stage to achieve a low stripping ratio.
Ultimate Slope
74
Composition of Monel Metal Alloy composition
Nickel and Copper
75
Minimum Concentration needed for Copper, Gold, Nickel, and Silver in ppm for mining
Copper - 3,000 ppm
Gold - 0.5 ppm
Nickel - 2,000 ppm
Silver - 500 ppm
76
Describe how the cooling process provides a way of sorting out and concentrating metals to a potentially mineable grade.
"Cool... Dump the dull stuff, skim off the cream"
As volcanoes erupt, pressure is relieved in the magma chamber allowing parts of its minerals to crystallize.
These crystals are usually silicates (refer to Bowen's on T and P changes) which are of no economic value leaving the melt/hydrothermal fluid enriched with precious metals.
Since magma input is not a one time event and volcanic eruption is also not a one time event, the melt/hydrothermal fluid will be super-enriched and will deposit precious metals on different levels as it travels upwards due to meteoric conditions.
77
True or False. A sulfur rich host rock is more important than a Copper/Nickel rich melt to produce heavy Ni-Cu sulfide melt.
True. Magma absorbs sulfur from surrounding rocks producing heavy Ni-Cu sulfide melt that settles in the bottom of the melt and cools to produce massive sulfide.
78
a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas
Greisen
79
Source most of world's Ni and PGE's, Cr
Mafic Layered Complexes
80
36% of Ni production is from:
Cu-Ni Sulfide Deposits
81
Cu-Ni Massive Sulphide deposit in Canada hypothesized to have caused by meteorite impact
a. Sudbury
b. Norilsk
c. Witwatersrand
d. Rossing
Sudbury
82
Cu-Ni Massive Sulphide deposit in Russia where mineralization is hosted by 6 separate intrusions that formed feeders to the Siberian Traps
a. Sudbury
b. Norilsk
c. Witwatersrand
d. Rossing
Norilsk
83
Cu-Ni Massive Sulphide deposit in Canada which was discovered in 1993. 4% of world Ni production.
a. Litseng
b. Norilsk
c. Voisey's Bay
d. Rossing
Voisey's Bay
84
PGE-Cr Deposit in South Africa which hosts 80% of world's PGE resources, and 60% of production. Average grade is 5-8 g/t.
a. Bushveld Complex
b. Norilsk
c. El Sauzal
d. Great Dyke
Bushveld Complex
85
PGE-Cr Deposit in Montana. Interbedded pyroxenites, dunites and gabbros. _Cr/Cu/Ni produced in WW2. It produced the 13% of world production of PGEs in 2005_. Average grade is 10 g/t.
a. Bushveld Complex
b. Stillwater Complex
c. Olympic Dam
d. Great Dyke
Stillwater Complex
86
PGE-Cr Deposit in _Zimbabwe_. Interbedded pyroxenites, dunites and gabbros. It produced the 270K oz Pt or 7% of world production. Average grade is <4 g/t.
a. Stillwater Complex
b. Muggaburna
c. Olympic Dam
d. Great Dyke
Great Dyke
87
Company founded by Cecil Rhodes when diamonds were discovered in a small mining town of Kimberley in South Africa.
de Beers company
88
Diamodiferous kimberlites almost always found above _______.
Archaean cratons (>2.5 BY)
89
Town that produced a 0.09 g/t grade of diamond
a. Letseng
b. Jwaneng
c. Orapa
d. Premier
a. Letseng (0.004g/t)
b. Jwaneng (0.09 g/t)
c. Orapa (0.24 g/t)
d. Premier (g,788 g/t)
90
The ______________ is the world's largest gold mine and the highest situated mine in the world.
Grasberg mine
91
What are the 3 ways to get gold to drop out of the fluid?
1. Cool the fluid or drop the pressure (Epithermal)
2. Chemical Trap (Magnetite + Gold/Sulfur thio-complex = Pyrite + Native Gold + Water) (Hydrothermal and Mesothermal)
3. Change pH or Eh (Mixing of Neutral Gold-bearing fluid with a reduced groundwater will cause the solubility of gold to drop) (Mesothermal)
92
High Sulfidation epithermal deposit in Mexico
El Sauzal
93
High Sulfidation epithermal deposits in Peru
Pierina and Yanacocha
94
Deposit that is:
- Mainly gold (+ minor silver and mercury)
- usually small/moderate in size but high grade
- Relatively narrow veins, steeply dipping
- Depth limited by boiling zone (pressure release)
Epithermal Low Sulfidation
95
Deposit characterized by:
- Gold near the surface (becoming more silver and lead-zinc rich at depth)
- Steep veins but may have flat splays
- Veins can be long and continuous
- Silver-lead-zinc mineralization can extend to significant depths
- underground or open pit
Epithermal Intermediate Sulfidation
96
These deposits are characterized by:
- Archean craton
- Thick crust to cause the deepest portion to melt
- "Crustal scale" fault to provide channelway towards surface
- Jog zone and source of reduced fluid to cause gold to drop out of solution.
Mesothermal/Greenstone Shear Zone Gold deposits
97
Are significantly clay rich limestones
Dirty Carbonates
98
This deposit is characterized by:
- hosted in "dirty carbonate" rocks
- Gold occurs as "micron gold" in disseminated pyrite
- associated with orpiment/realgar, carbon, silicification
Carlin deposits
99
This deposit produced 40% of all the gold produced in the world since the beginning of time.
Witwatersrand Gold Deposits
100
This country has the largest Uranium resources in the world:
a. Kazakhstan
b. Canada
c. Australia
d. Niger
Answer: Canada
Kazakhstan (largest production)
101
An IOCG Uranium deposit:
a. Witwatersrand
b. Rossing
c. Olympic Dam
d. Cigar Lake
Olympic Dam
102
An Intrusive Uranium deposit:
a. Witwatersrand
b. Rossing
c. Olympic Dam
d. Cigar Lake
Rossing
103
Uranium occurs as fine-grained uraninite and uranophane. Low grade but large and easily extracted.
a. Witwatersrand
b. Rossing
c. Olympic Dam
d. Cigar Lake
Rossing
104
Uranium is soluble in _________ water
Oxidized (Dissolve in oxygenated ground water, precipitate in reduced ground water)
105
What are the major minerals associated with albitic alteration?
Albite and paragonite
106
What are the major minerals associated with argillic alteration?
Kaolinite, smectite, illite; occurs in gold deposits hosted by sedimentary rocks
107
What are the major minerals associated with phyllic alteration?
Sericite, quartz, pyrite; decomposition of silicic rocks
108
What are the major minerals associated with potassic alteration?
Biotite, K-feldspar, adularia; High T alteration of silicic magma
109
What are the major minerals associated with propylitic alteration?
Chlorite, epidote, actinolite, tremolite; low to moderate T decomposition of mafic rocks
110
What are the major minerals associated with Spilitization alteration?
Albite
111
What is an ore?
a. accessory mineral in igneous rocks
b. any mineral of economic value
c. mineral which can be extracted with profit
d. rock of economic value
mineral which can be extracted with profit (the most correct answer)
112
'Tenor' in respect of an economic mineral deposit refers to what?
a. quantity of metal or element
b. amount of gangue
c. regularity of mineral content
d. level to which the deposit has been metamorphosed
quantity of metal or element
113
What is stope in a mine?
a. incline leading to an underground mine
b. cut on the side of mine tunnel
c. excavation formed by extraction of ore in a mine
d. main part of underground mine
excavation formed by extraction of ore in a mine
114
Which unit is used in the context of weighing precious metals and is equal to 1.555 grams?
a. troy ounce
b. carat
c. pennyweight
d. deadweight tonnage
Answer: pennyweight or deadweight tonnage
a. **troy ounce** - same concept, but 20 times (or 31.1035 grams)
b. **carat** - 200 mg, used to weigh precious gems
115
How does supergene enrichment of a mineral deposit takes place?
a. by upward capillary movement of solutions
b. by oxidation of sulphide minerals
c. when deposits lie along water table
d. by descending solutions
by oxidation of sulphide minerals (most correct)
116
What is efflorescence?
a. bubble formation on application of acid on a carbonate
b. mineral encrustation on soil
c. luminescence caused by electromagnetic radiation
d. luminescence caused by cathode rays
mineral encrustation on soil
117
What is a wall rock in economic geology?
a. rock in which minerals occur
b. vertical mineralized dyke
c. rock adjacent to a mineral vein
d. mineralized face of a mine
rock in which minerals occur
118
Which of the following is not a noble metal
a. platinum
b. tellurium
c. gold
d. palladium
tellurium
119
Which one of the following minerals does not occur in or as a
sedimentary deposit?
a. manganese
b. pyrite
c. barites
d. talc
talc
120
What is the special property of fuller's earth
a. expands with addition of water
b. highly absorbent
c. high plasticity
d. good bleaching agent
highly absorbent
121
Historically, which country had the reputation as the first major
producer of diamonds?
a. Brazil
b. Borneo
c. India
d. South Africa
India
122
That diamond is pure carbon was proved first by which chemist?
a. Antoine Lavoisier
b. Smithson Tennant
c. Linus Pauling
d. Marie Curie
Smithson Tennant
123
The largest diamond ever found, the Cullinan, weighed how much in the
rough?
a. 4112 ct
b. 4238 ct
c. 3106 ct
d. 3144 ct
3106 ct
124
Where is the world-famous 'Koh-i-Noor' diamond kept now?
a. Tower of London
b. Royal treasury, London
c. Buckingham Palace, London
d. Sandringham Palace, Scotland
Tower of London
125
The largest cut blue diamond now displayed in the museum of the
Smithsonian Institution, Washington DC, USA, is known by which name?
a. Brunswick
b. Tavernier
c. Hope
d. Cartier
Hope
126
Which is the mineral that is mined from under the sea off the coast of
Namibia?
a. copper
b. zircon
c. titanium
d. diamond
Diamond
127
What is an ashlar?
a. briquette of fly ash
b. stone slabs for roofing
c. rectangular stone for building
d. a heap of stone
rectangular stone for building
128
The element of this ore is added to capacitors to regulate voltage and improve audio quality of mobile devices
a. Tantalite
b. Bastnaesite
c. Sphalerite
d. Bauxite
Tantalum from Tantalite ore
129
_\_\_\_\_ is a source of REE used to produce magnets in speakers, microphones, and vibration motors.
a. Tantalite
b. Bastnaesite
c. Sphalerite
d. Bauxite
Bastnaesite
130
_\_\_\_\_ is the source of indium and germanium used in a mobile phone's screen.
a. Tantalite
b. Bastnaesite
c. Sphalerite
d. Bauxite
Sphalerite
131
Gallium provides LED backlighting. What ore is the source of this commodity?
a. Tantalite
b. Bastnaesite
c. Sphalerite
d. Bauxite
Bauxite
132
This type of Silver has a fineness of 925.
a. Britannia Silver
b. French 1st Standard
c. Sterling Silver
d. Scandinavian Silver
Answer: Sterling Silver
a. Britannia Silver (958)
b. French 1st Standard (950)
d. Scandinavian Silver (830)
133
It is the core of Nobel Prize metals. What are the elements present?
a. Cupronickel
b. Nordic Gold
c. White Gold
d. Green Gold
Answer: Green Gold (Au, Ag, Cu)
a. Cupronickel (Cu, Ni - coins)
b. Nordic Gold (Cu, Al, Zn - Euro coins)
c. White Gold (Au, Pd, Ni - jewelry)
134
It is a Shape Memory Alloy (SMA) used for specialized glass frames. What are the elements present?
a. Nichrome
b. Nitinol
c. Mischmetal
d. Pewter
135
Which environment/setting would you expect to find gold and tungsten?
a. Magmatic Arc
b. Continental Rift/Hotspot
c. MOR
d. Shield
Shield
136
Which environment/setting would you expect to find chromium and platinum?
a. Magmatic Arc
b. Continental Rift/Hotspot
c. MOR
d. Shield
MOR
137
Alteration zone with abundance of biotite, k-feldspar, and adularia
Potassic
138
Alteration zone with abundance of chlorite, epidote, and actinolite
Propylitic
139
Alteration zone resulting in bleaching out of feldspars and introduction of clay minerals.
Argillic
140
Alteration zone with assemblage of kaolinite + quartz + hematite + limonite
Advanced Argillic
141
Layered Mafic Intrusions in South Africa and Canada
Bushveld and Sudbury
142
Olympic Dam and Prominent Hill in Australia are what type of a mineral deposit?
Iron Oxide Cu-Au (IOCG)
143
What type of epithermal deposit is found in Lepanto?
High Sulfidation
144
Where can Cyprus-, Besshi-, and Kuroko-type VMS found in Philippines?
Barlo, Rapu-Rapu, and Bagacay respectively
145
What is the use of BARITE in drilling?
DRILLING MUD
146
What country mines gemstones?
a. Sri Lanka
b. Madagascar
c. Goa
Sri Lanka
