Question for Day 3: finals Flashcards
These are zones of increased content of chemical elements in natural formations associated with deposits of useful minerals
Halos of Dispersion
It is endogenic and arises in the surrounding rock simultaneously with the formation of the mineral body.
Primary halo
Form in the products of decomposition of rock, and also in soil, water, plants, and the surface atmosphere as a result of supergene processes taking place on the land surface
Secondary Halo
It is a sampling method where a specimen is picked up from a portion of mineralized outcrop/ore body
Grab sampling
Suitable method for bedded, banded, and vein types of deposits, this method consists of cutting channels across the face of exposed ore and collecting resulting chips, fragments and dust from each channels to make a sample.
Channel/ Groove/ Trench sampling
Enumerate the steps in conducting channel sampling
- The outcrop is cleared from unwanted materials
- If necessary, the rock face may be trimmed at cutting point of the deposit
- The location of channel is marked by a set of parallel lines
- The inner part is excavated keeping a constant channel cross section
- Finally, excavated material is collected, pulverized carefully and sampling site is labeled The cutting of channels depends on ore body or metal deposit
Used for hard or uniform ores where it is difficult to cut channels. The samples are collected by taking a small series of chips of rocks on a regular grid pattern from the working face in regular intervals
Chip or point sampling
Involves cutting of pieces of ore and rock from exposed faces of ore and waste The faces may be natural outcrops or faces exposed in surface trenches and pits or in the backs, walls, and floors of development openings and stopes
Face/ Muck/ Lump Sampling
Face samples may be taken from_____. Please enumerate.
- by cutting grooves or channels of uniform width and depth across the face or sections of the face or
- by picking off small pieces all over the face, more or less at random
- The former method is the more systematic, and although ordinarily it is the one that is employed when accuracy is desired, pick sampling may sometimes be as accurate, or more so, depending on conditions
This type of sampling method is used in checking of the reliability of other types of samples and sometimes may be taken to determine a correction factor for use in an estimate based on samples of other types
Bulk sampling
The samples are taken by blasting down drift blocks or a section in a stope or otherwise obtaining a sample of several tons to several hundred or even thousands of tons, either from trench, pit, channel or from the run of mine, where the entire lot is milled separately
Bulk sampling
Collection and analysis of silt, sand, mud, clay in a stream or river bed, either dry or wet
Stream sediment sampling
Usually employed as an early stage exploration tool to cover large areas relatively quickly in the hope of identifying smaller areas of interest to be followed up with prospecting and more detailed (and costly) sampling techniques
Stream sediment sampling
This method is more convenient for the determination of the deposit’s boundaries. Here, samples consists of the cuttings from drill holes
Drill hole sampling
Enumerate the various error of sampling
- Improper spacing in samples
- Insufficient number of samples
- Improper location of samples
- Incorrect weighting of assay
- Failure to recognize ore, thus leaving it unsampled
- Improper chemical analysis
What sampling pattern involves acquisition of samples that are equally spaced apart, both vertically and horizontally
Regular
Simplest grid design because all the samples are equally spaced apart vertically and horizontally
Regular grid
Samples are equally apart horizontally. Every other sample line is offset one half sample spacing which decreases the diagonal spacing between samples
Staggered grid
Each sample has same distance of away from each surrounding sample. This pattern is sometimes called a triangular grid because 3 nearest samples form an equilateral triangle
Equidistant grid
It is considered the most reliable method for accurately determining the content of gold, silver, and platinum group metals (except osmium and ruthenium) in ores or concentrates This process involves melting a gold bearing sample in a clay crucible/cupel at 1000 C with a mixture of fluxes (such as silica and borax), lead oxide (called litharge), and a reducing agent (frequently flour)
Fire assay
The process of extracting sulfur from underground deposit.
Frasch process
Smelting process in high temperature conditions
Pyrometallurgy
What process refers to the dissolution of silver in a dore during boiling in nitric acid?
Parting
Heat treatment of a material to change its ductility.
Annealing
Separating the silver and gold by melting its impurities.
Cuppellation
Dissolving the solid (ore) into the acid.
Chemical digestion
Cyprus, Kuroko, and Besshi type VMS deposits can be found in what areas in the Philippines, respectively?
Barlo (pangasinan) - Bagacay (samar) - Rapu-rapu (albay)
What is the strongest acid?
Flouroantimonic acid
Who was the infamous Filipino geologist who salted crushed core samples with gold shavings in Busang East Kalimantan, Indonesia in 1997
Michael De Guzman
What is the most common coal rank in the Philippines?
Subbituminous coal
Where can we found cinnabar in the Philippines? The powdered cinnabar used for pigment is called _______.
Palawan; Vermillion