Showing posts with label Mining Technologies. Show all posts
Showing posts with label Mining Technologies. Show all posts
Monday, 13 August 2018
Wednesday, 21 March 2018
Mount Crater Gold Mine in Papua New Guinea
March 21, 2018Learning Material, Mine Waste Management, Mines in PNG, Mining Technologies, Mt.Crater Gold Mine
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Crater Gold Mine is located in the western part of Eastern Highlands Province in Lufa District,
adjacent to the eastern border of Simbu Province bordering Kramui Nomane District. It is centered
50 Km southwest of Goroka, the capital town of Eastern Highlands Province.
The closest airstrip is the Guasa Airstrip. From Guasa airstrip it will take you about 2 - 3 hours walk up the steep hills and along the fast flowing rivers. The site is ussually assessed by shopper.
ML510 was granted to Anomaly Limited in November 2014 to carry out a small scale underground
mining and processing operation at Crater Mountain.
Prior to the Mining Application and due processes were followed for granting, there was an exploration license EL 1115 which was known as Nevera and Nimi Prospects. The exploration could have started long ago back in the 1980s and various PNG National geologists as well as foregne geologist can recall this prospect. The EL 1115 started in 1994 when the exploration licence was granted initially to MACMIN and then jointly explored by BHP. It was then to Anomaly Limited. Anomaly then tirelessly continued the exploration until the mineral resource was defined and further intended to apply for a mining lease to developed the ore body which was defined.
Mineralisation is typically confined to veins and thus dictate the Mining Method to be sub-level caving. The operation utilities hand-held rock drills and jack picks. Broken ore is transported via mini rail cars to surface for processing.
Tailings discharge from the mill is collected in a sump where solids settle and the water overflow is
channelled into a second sump to further settle any silt and clear water overflows out to the nearby
creek. The solids in the sumps are harvested periodically and stockpiled for further processing at a
later stage.
Thus, it is believed that mine waste is managed within the vicinity and less environmental impacts are anticipated in this operation.
adjacent to the eastern border of Simbu Province bordering Kramui Nomane District. It is centered
50 Km southwest of Goroka, the capital town of Eastern Highlands Province.
The closest airstrip is the Guasa Airstrip. From Guasa airstrip it will take you about 2 - 3 hours walk up the steep hills and along the fast flowing rivers. The site is ussually assessed by shopper.
ML510 was granted to Anomaly Limited in November 2014 to carry out a small scale underground
mining and processing operation at Crater Mountain.
Prior to the Mining Application and due processes were followed for granting, there was an exploration license EL 1115 which was known as Nevera and Nimi Prospects. The exploration could have started long ago back in the 1980s and various PNG National geologists as well as foregne geologist can recall this prospect. The EL 1115 started in 1994 when the exploration licence was granted initially to MACMIN and then jointly explored by BHP. It was then to Anomaly Limited. Anomaly then tirelessly continued the exploration until the mineral resource was defined and further intended to apply for a mining lease to developed the ore body which was defined.
Mineralisation is typically confined to veins and thus dictate the Mining Method to be sub-level caving. The operation utilities hand-held rock drills and jack picks. Broken ore is transported via mini rail cars to surface for processing.
Tailings discharge from the mill is collected in a sump where solids settle and the water overflow is
channelled into a second sump to further settle any silt and clear water overflows out to the nearby
creek. The solids in the sumps are harvested periodically and stockpiled for further processing at a
later stage.
Thus, it is believed that mine waste is managed within the vicinity and less environmental impacts are anticipated in this operation.
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Photo Courtesy of Anomaly website |
Wednesday, 14 February 2018
Environmental Impacts of Artisanal and Small Scale Gold Mining in Papua New Guinea
February 14, 2018Artisanal Small Scale Mining, Gold, Learning Material, Mine Pollution, Mining Technologies, Safe Handling of Mercury
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Mechanize Small Scale Mining
Artisanal and small scale
gold mining (ASSM) offers lucrative employment opportunities to the locals of
most developing countries. The major drawback of ASSM is its impacts on the
environment as a result of improper mining and processing techniques. Exposed
and disturbed lands are usually subject to soil erosion and avalanches of
debris in active ASSM areas. Mercury is commonly used to concentrate gold, and
if not handled properly causes pollution of life supporting river systems.
Small
scale gold miners in many developing countries rely primarily on deposits
containing free gold and may be classified as shallow/deep alluvial or lode
type. The mining method used in artisan small scale gold mining employ very
basic technology. Shallow alluvial deposits are commonly found in valleys and
streams at depths not more than two meters. Deep alluvial deposits are found
along major riverbanks and older river courses, and usually at depths exceeding
six metres along the banks of rivers. The lode type of gold deposits is usually
composed of partially weathered gold bearing reefs, which are either outcrops
or near surface deposits. In Papua New Guinea, active artisanal mining are
commonly found abandoned mining areas like Panguna and Missima and also near
operating mines like Porgera, Eddie Creek in Wau Bulolo, Morobe Province. Not
only that but also other parts of the Provinces also have active small scale
miners. Other provinces include but not limited to: East Sepik, Sandaun, Enga,
Western, Eastern Highlands, Jiwaka, Madang, Western Highlands, Oro, Milne
Bay,Morobe.
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The small scale gold fields are mainly
riverine deposits where mining occurs along river banks, terraces and in active
river channels. Using poorly constructed sluice boxes, gold bearing material is
fed into the inclined sluice boxes. The box is constructed using plywood or
flattened roofing iron with wooden/metal ripples. These types of operations are
associated with low to very low recovery because of uncontrollable river flow
rates, incorrect inclination of the sluice boxes and inappropriate amounts of
feed material at any one time. It is extremely difficult to introduce
mechanised alluvial mining because of low skills and knowledge, isolation from
transport infrastructure and lack of basic infrastructure.
The
gold bearing gravels are concentrated by rippled sluice boxes. The fine gold is
not commonly trapped in the ripple compartments. The fine particles of sand
with gold in it are than poured into the panning dish for further panning. Mercury
is placed in into the panning dish to concentrate the fine gold particles.
Amalgamation is an efficient mean of extracting gold particles from
concentrates after panning or sluicing.
Health
and environmental impacts (Watch Video)
The
artisanal and small scale gold mining provides employment at local and national
levels, and the sector is an important source for the inflow of foreign
exchange into rural communities. However, small scale mining activities are
associated with sensitive health and environmental issues.
The
process of recovering gold by retorting and heating the amalgam over an open
fire is a dangerous practice. The open fire could be in houses or at river
banks and thus a whole family could be exposed to poisonous mercury fumes.
Concentrate from
sluicing near streams is usually mixed with mercury and a considerable amount
of mercury is lost to the streams. Apart from direct inhaling of mercury fumes
by miners, aquatic life also feeds on mercury lost into the river, which are
then eaten by the locals through the food chain. The Watut and Bulolo Rivers
has been subject to prolonged mercury contamination and discharges of
hydrocarbon wastes. The Watut people depend on the river for fishing, washing
and farming on the river banks.
Some miners in old
shafts and adits and they are consequently exposed to the trapped noxious gases
such H2S. Locals have been reported that they are buried alive when they burrow
through soft oxidized lodes or vein systems.
Some operators
locate their sluice boxes in streams, thus polluting the water. Silting and
stream discolouration are very common. Farmlands are usually destroyed by
mining activities. Locals even uproot big trees along structurally defined thin
gold deposits. Sometimes, the narrow gullies are not rehabilitated and are left
to be taken care of by nature.
Exposed and
disturbed lands are subject to soil creep widening the flow channels, and
debris avalanches are common along rivers at the active mining areas. The loss
of fertile land due to small scale mining puts socio-economic pressure on the
local society. Old gravel pits are usually abandoned without reafforestation.
Pits filled with stagnant water are common.
Education and training
Small-scale
mining technology in most developing countries is simple and attracts many
unskilled people. The desire for economic and social survival has attracted
many people to the industry. The law expects the licensed small-scale miner to
mine using effective and efficient methods, and observe good mining practices,
health and safety and protect the environment.
The Small Scale
Mining Branch of PNG Mineral Resources Authority (Formerly Department of
Mining) in Wau, Morobe Provine has created education and training materials for
the miners. The Department has produced seven booklets and DVDs on
•
Simple Gold Mining;
• Basic Mining Practice;
• Advanced Mining practice;
• Handling of Mercury;
• Occupational Health and Safety;
• Environmental Issues; and
• Economics of Mining.
The major focus
of the training resources is to ensure that small scale operations are safe,
environmentally friendly and economically viable.
Small-scale
mining operations in most developing countries have serious negative environmental
impacts. One of the major factors is the implementation of the associated
mining Acts which are lacking.
Donor agencies
like the World Bank, European Union and Japanese International Cooperation Agency
(JICA) have in recent times shown keen interest in the negative and positive
impacts of the PNG’s ASSM sector. AusAid and the World Bank have sponsored the
building of the ASSM sector capability in PNG through legislative framework and
training and awareness on the use of mercury.
Note: This article is a reproduction of a learning material with inclusion of up to date information.
Reference
[1] Ail, K. K. (2005. Kwoe River
Alluvial Gold Deposit Evaluation and Development Plan, PNG University of
Technology, Lae.
Saturday, 3 February 2018
Osarizawa Mine in Akita Prefecture, Japan
February 03, 2018Learning Material, Mining Regulators, Mining Technologies, Osarizawa Mine in Japan, Training
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Osarizawa Underground Mine Adit |
Osarizawa mine is an abandoned mine in Akita Prefecture,
Japan. Event though the mine is closed, the mine site is kept for sightseeing
purposes. The Osarizawa mine deposit is
a vein type deposit which was discovered in 708. The oldest Literature of
the mine was written in 1599 about the discovery of the Gojumaizawa gold
deposit which is part of the mine. The main commodities produced by the mine
were gold and copper.
The vein deposit was mined using the shrinkage stope mining method.
There are 15 levels and are 30m apart in height. The Total perimeter of the
mine levels is 700 km. The area of the mine site is 3km N-S by 2km E-W ~ 6km2 . Ceiling is 2-3m in
width.
The Level Zero starts at RL of about 300m and this is where the
access adit (ingress) is built. There are
5 levels above the zero level and 10
levels below zero level. The mining progressed upwards and mined materials were
collected at lower levels with the aid of gravity.
The host rock of the ore deposit is silicate mudstone which
is 10 times harder than concrete. Since the host rock is highly competent, the mine
was almost unsupported and less artificial support. Few supporting materials used
were logs/timbers of about 10mm to 300mm in diameter which were fitted well in between
mined out areas to prevent wall collapse. Other artificial supporting methods
are roof bolts, Mass wires and steel spiral cables drilled upwards to prevent
rocks from falling. Timbers are replaced every 10 years. The other supporting method used was the backfilling of
mined out areas with waste materials. Underground water is effectively under control
by plastic roofing gutters and drained out along the side of the concrete
pathway at each level.
The mined out ore/materials were transported by mini rail cars
which are powered by batteries. The rail cars were attached to one another like
train cars. The railways were built for these small battery powered rail cars. The
drilled or broken ores were loaded onto the rail cars and it required either
one or two operators to transport the materials out of the mine via shaft by
way of hoisting. At Zero Level the rail cars were driven out via the adit and
further to the processing plant for processing.
Production increased
with the increase in the rail cars.
Note:This article is an observation report and may not contain factual and detail information. The information here is kept at high level only. This article is subject to change if need be.
Wednesday, 3 May 2017
Mining Technology Innovations in History
The First gold mining commenced in the ancient Egypt as early as 5,000 years ago. There were four Historical Innovations in the Mining Technologies which greatly contributed to the progress in mining which include:
Ref: Jiro Yamatomi, A Fundamental Lecture on Mining Technologies from MINETEC, October 2015
- Explosives
- Steam engine
- Froth flotation
- Electrochemistry
Explosives
- The Black Powder is invented in the Tong Dynasty of China (618~907 AD) and is included among the great four inventions of the medieval China along with paper, printing and compass.
- Early Applications of black powder for mining were recorded in Germany in 1613 and in Hungary in 1627.
- Dynamite is the origin of modern explosives was invented by Alfred Nobel in 1866. Thereafter, safe and effective rock breakage was successfully practiced both in civil engineering works and mining operations.
Steam Engine
- Before Industrial Revolution, invention of steam engines, natural energy such as water flow, wind, human muscle, animal power, gravity force, etc is only used for drainage, ventilation, transportation..
- Thomas Newcomen invented Newcomen steam engine in 1712 which was the first practical device to utilize the power of steam to produce mechanical work, principally to pump out water from coal mines.
- However, Newcomen engine was costly to operate because of its insufficiency caused by heat loss.Newcomen engine was gradually replaced by James Watt's improved engine introduced in 1769.
- By using steam engines, mining was getting into deeper and larger scaled operations.
Froth Flotation
- The modern froth flotation process was invented in the early 1900s in Australia. Before the flotation technology was available, ore and waste minerals were generally separated by using differences in specific gravity, but hardness and friability /abrasiveness may also affected the separation.
- Using froth flotation create possibility in separation of valuable minerals from gangue minerals by taking advantages of differences in their hydrophobicity. The flotation process is used for the separation of a large range of sulfide, carbonates and oxides prior to further refinement.
- Flotation process is widely used in modern mining to effectively to correct useful minerals and to efficiently concentrate worthy minerals from lower grade ore.
Electrochemistry
- Modern Copper refining utilizes the electrolysis to purify blister copper upgrading to refined copper with higher grade ore over 99.99% Cu. In Copper electro-refining, large slabs of blister copper serve as the anodes and thin sheets of pure copper serve as the cathodes in an electrolytic cell filled with copper sulfate solution, CuSO4. Application of a suitable voltage to the electrodes causes oxidation of copper metal at the anode and reduction of Cu2+ to form copper metal at the cathode, since the copper is both oxidized and reduced more readily than water.
- The impurities in the anode including gold silver can be collected below the anode as anode sludge.
- Electrochemistry also contributes to the hydro-metallurgical recovery of metals, such as SX/EW.