IV. Nickel Flashcards
Principal Nickel Minerals:
- Garnierite 2. Millerite 3. Niccolite 4. Pentlandite 5. Pyrrhotite
What is the appearance and magnetic property of Nickel?
Nickel is a silvery white, magnetic metallic element.
Nickel specific gravity
8.9
Nickel is ___ most abundant element in the earth’s crust
22nd
Hardness
3.5
What are the types of productive nickel deposits in the world?
sulfides and laterites
Which types of nickel deposits occur in the Philippines, and which type has been historically more economic?
Both sulfide and laterite deposits occur in the Philippines, but the laterite deposits have historically been more economic
What economically recoverable element is commonly found in nickel laterites?
cobalt
What is the origin and deposit type of sulfide nickel mineralization associated with magmatic segregation in the Philippines?
Magmatic segregation leads to magmatic nickel sulfide deposits, occurring as sulfide blebs in dunite. Type locality: Acoje, Sta. Cruz, Zambales.
Where are magmatic nickel sulfide deposits with chromite inclusions found in the Philippines?
Mariwara, Narra, Palawan.
What is the origin and occurrence of epithermal nickel deposits in the Philippines?
Epithermal nickel deposits form through hydrothermal processes, occurring in shear zones and hot springs. Type locality: Minluhlo, Jaro, Leyte.
What type of nickel mineralization occurs as an accessory metal in high-sulfidation copper veins in the Philippines?
Hydrothermal nickel mineralization. Type locality: Binmaca, Pasuquin, Ilocos Norte.
What is the origin and occurrence of laterite nickel deposits in the Philippines?
Residual concentration results in nickel laterites (± cobalt), occurring in the limonite zone. Type locality: Nonoc Island, Surigao del Norte.
What type of nickel mineralization is associated with the saprolite zone in the Philippines?
Laterite nickel deposits from residual concentration. Type locality: Rio Tuba, Bataraza, Palawan.
What are nickel laterite deposits derived from, and where are they commonly found in the Philippines?
Nickel laterite deposits are derived from the weathering of underlying ultramafic rocks found along the ophiolite belts of the country, forming the bulk of nickel deposits.
How is a laterite deposit defined in terms of its zonation?
A laterite deposit is defined as having a limonite zone on top of a saprolite zone.
What elements are commonly found in the nickel ore within the limonite and saprolite zones of a laterite profile?
Both the limonite and saprolite zones of the laterite profile contain nickel ore with variable amounts of iron, cobalt, magnesium, manganese, silica, alumina, and chromium.
What is the composition and characteristic of the limonite zone in nickel laterite deposits?
The limonite zone is composed predominantly of iron clay minerals and is usually capped by reddish-brown soil with low nickel content. The capping, termed as overburden, is low in nickel but rich in iron, as indicated by the presence of iron pisolites or hard caps.
What is the typical appearance and color variation of the saprolite zone in nickel laterite deposits?
The saprolite zone exhibits various shades of green mixed with hues of yellow and brown. As it approaches the bedrock, it turns into shades of blue, gray, or black.
How does the iron and magnesium content change within the saprolite zone compared to the limonite zone?
The iron content in the saprolite zone becomes significantly lower than in the limonite zone, while the magnesium content progressively increases at depth.
What causes the higher ore grade in the saprolite zone, and what mineral is commonly associated with green coatings along fractures?
The higher ore grade is due to the downward migration of nickel, which settles along cracks in the saprolite. The ubiquitous green coatings along fractures are often due to garnierite, a high-grade hydrous nickel silicate belonging to the serpentine group of minerals.
closely associated with chromitites and platinum group elements (PGE)
Magmatic Nickel Sulfide Deposit
occurs in narrow silicified zones in serpentinite rock
and in rocks immediately adjacent to it
Hydrothermal Nickel Sulfide Deposit
What are magmatic nickel sulfide deposits closely associated with?
Associated with chromitites and platinum group elements (PGE).
Where were magmatic nickel sulfide deposits reported by Bacuta (1989)?
Four occurrences in the Acoje block of Zambales Ophiolite.
What did Santos (1993) report regarding magmatic nickel sulfide deposits?
Nickel sulfide inclusions in chromite deposits of Central Palawan.
What is the average grade of nickel sulfide deposits in the Philippines?
Average grade of 0.23 to 0.47 % Ni.
What forms do magmatic nickel sulfide deposits take?
Pentlandite, nickel-copper-iron alloys, nickel-rich pyrrhotite/marcasite.
How do magmatic nickel sulfide deposits occur in ultramafic rocks?
Blebs, inclusions, hairline stringers, or veins in ultramafic rocks.
