Importance of Mining
Precious metals play a central responsibility in the modern world. With an ever-developing technological world, the demand for copper and gold has increased since the technological revolution. Due to their high conductivity strength, tech giants are employing them in making micro-processors and cables and wires. Other physical characteristics of copper and gold that make them the most suitable materials to utilize in electronics are their ductility and malleability. This means that copper and gold can be stretched into thin wires and pressed into thin sheets, hence, copper and gold wires can be made thin and lightweight while still maintaining their physical form and conduct electricity soundly.
Even before the technological revolution, gold had always been an essential commodity in society. The amount of gold one person has defines their wealth and status in society. One of the most renowned applications of gold was exercised by the Ancient Egyptians. Pharaohs used to cast coffins called sarcophagi from solid gold. Gold were so common back then that the pharaohs and the wealthy used to stuff their pyramids and tombs with riches consisted of mainly gold to take with them to the afterlife. Gold was and still is melted, casted, and shaped to make jewelry. Jewelry is a way of exhibiting someones wealth. All across civilizations and ages, the amount of jewelry someone wears usually define their status and wealth. The more jewelry one wears, the wealthier one is and the higher statute one has. Up to this day, people still judge how wealthy somebody is from the amount of jewelry they own and wear.
The use of these metals is not as important as how to get them. Gold is only useful if we can play around with it, not when it is still underground. The main way to obtain these precious metals is through mining. Mining, in general, involves the following processes. One, the ore is extracted from the ground. Two, the ore undergoes separation and processing. Three, the concentrate is refined and purified. The resulting product is not pure gold or copper. Instead, most of the time, the finest form of gold and copper, is 99.99% gold or copper as there will always be impurities in the substance.
Currently, around 60 percent of the gold production is used for jewelry, 40 percent for investments (for example central bank reserves as a hedge against inflation or recession), and 10 percent for industries. Where large deposits of valuable minerals are located, large mines will be found, if not, constructed and where large mines are located, industries will play a vital role in the local community. Consequently, if we are to remove the mining industry from that area, the local economy would simply fail. That’s why once a mining community has developed, we cannot simply halt every mining activity in the area.
The Grasberg Mine
The Grasberg Mine is located in the island of Papua in the Indonesian archipelago, more accurately on Puncak Jaya in the Tembagapura region. The name Tembagapura literally translates to copper temple in English. The Grasberg Mine has the worlds largest gold reserve and the second largest copper deposit and is the largest and third largest gold and copper mine in the world respectively. Its location on Puncak Jaya, the highest point on the New Guinean island, made its construction a herculean task. Located 4,100 meters above sea level, the Grasberg Mine mines a deposit of copper with a proven and provable reserve of 2.8 billion tonnes of 1.09%. The reserves also contains 0.98g/t gold and 3.87g/t silver.
The geology at the mine is nested coaxial porphyry ore-bodies and sulphide rich skarn at the margins; Eocene clastic carbonates with siltstones/sandstones. The mineral it mines is a chalcopyrite dominant porphyry skarn which goes through extraction processes such as crushing, screening, milling, and flotation to produce the wanted metals. The mine stands on the collision between the Indo-Australian and the Pacific tectonic plates. The mine consists of an open pit mine, an underground mine, and four concentrators.
The Grasberg Open Pit, over the course of almost three decades, has decreased the original elevation of the mine from 4,100 meters to 3,000 meters. In 2006, its annual production was 610,800,000 kilograms (copper), 58,474,392 grams (gold), and 174,458,971 grams (silver). It is mainly owned by Freeport-McMoran Copper and Gold with the Indonesian government owning 9.3% of it and is operated by PT. Freeport Indonesia, a subsidiary of Freeport-McMoran.
The mine utilizes 170 LHD (load-haul-dump) trucks, 65 dozers and graders, and a coal-fired power station to supply the Grasberg operations. Production from the open pit mine and the underground mine, the Deep Ore Zone (DOZ), adds up to a daily average total of 225,000 tons of ore to the mill and 135,000 tons to stockpile. After being crushed in the mine, the ore undergo further crushing and grinding at the mill. The crushed ore undertake flotation to separate the concentrate from the ore itself. The slurry goes through three pipelines to the port in Amamapare where it is dewatered and dried. The concentrate is then shipped to different smelters around the world.
The Froth Flotation Process
The froth flotation method takes advantage of the hydrophobicity of certain substances to separate them from impurities in the ore. For example, in the case of the Grasberg Mine, the type of mineral found there is chalcopyrite (CuFeS2). This chalcopyrite does not exist in its pure form underground. It is mixed with other impurities such as silt, sand, and other tiny particulates. The purpose of the froth flotation process is to remove as much of these impurities as possible and produce a high concentrate slurry consisted of 25% chalcopyrite which will later be sent to smelters around the world to be further extracted and purified.
Before performing froth flotation, the ore, first, undergoes crushing. The raw ore is placed in a large crusher, containing large steel balls that crush the raw ore to an almost powder-like state. The granularity of the ore has to be carefully maintained as the grind must be fine enough to liberate the mineral grain from associated rock, but producing too small a particle size is both expensive and detrimental to recovery. The crushing is usually done in water, producing a slurry called the pulp.
The pulp is placed in a series of flotation cells called roughers, collectors, and scavengers. It is in these cells that the chalcopyrite is being separated from other impurities. Several chemicals used in this process are classified into three categories: frothers, collectors, and depressants.
Frothers are used to produce the froth or foam used in the process. The froth must be strong enough to support the weight of the mineral floated and yet not be tenacious and non-flowing. It should have the tendency to break down when removed from the flotation cell. The froth produced by the frother should not coagulate in the water. Common frothers include pine oil, certain alcohols, and low molecular weight polypropylene glycols.
The collector functions as the media for which the mineral can be made hydrophobic. This allows them to stick to the tiny air bubbles and get carried to the froth bed. How the collector works is it increases the air-water contact angle on the mineral, allowing it to float up to the surface. Chemicals used as collectors are oils, xanthates, dithiophosphates, petroleum sulfonates, and fatty amines.
The role of depressants in a froth flotation cell is to improve the mineral selectivity efficiency by rendering unwanted materials that initially floated up with the wanted mineral hydrophilic (water-loving). These unwanted materials will sink to the bottom of the cell. Depressants usually take the form of pH modifiers. Lime is one of the most common pH modifiers; however soda ash should be used in the Grasberg Mine as lime is a depressant for gold particulates.
Section 1: Economy
Effects on Papua
In a place where mines are usually built, there is a high tendency that mining communities will spring up. In the 1920s, before the arrival of Freeport, Papua to Indonesia was like the Amazon rainforest to Brazil. It was inhabited by local tribes an cannibals. The Indonesian half of Papua New Guinea was covered by dense thickets of jungle, untouched by civilization and urbanization.
The Mimika regency has experienced considerable growth since the building of the Ertsberg and Grasberg Mine. The Mimika Regency is in the top 5 regencies and cities with the highest Human Development index (HDI) in Indonesia in 2014. In 2017, the Mimika Regency has an HDI of 72.42% while the whole province of Papua has an HDI of 59.09% which is a result from an average growth of 0.66% from its HDI in 2010. This indicates that the Mimika Regency and Papua as a whole has experienced significant growth in terms that its population have a higher life expectancy, better healthcare, better education, and higher income than what it used to have before.
Timika, the capital of the Mimika Regency, have also been subject to population influxes coming from other parts of Papua and Indonesia caused by employment opportunities. The population of the Mimika regency, in 2017, was 201,677, mae up of 113,126 males and 88,551 females. The Grasberg Mine employs over 18,000 workers both directly and indirectly or around 11% of the local population.
Freeport Indonesia, in charge of running the mine, has invested millions of dollars in economic and agro and aquaculture development programs to develop sustainable livelihoods independent from the mining sector. These programs include encouraging and financially supporting vegetable, coffee, cocoa, coconut, and karaka (mangrove crab) production programs. Through its Micro, Small, and Medium Scale Enterprise program (MSME), Freeport Indonesia has assisted these programs with money and training of 118 Papuan entrepreneurs, 102 of them coming from seven tribes indigenous to the area.
So far, all economical impacts of the Grasberg Mine looks positive, but the increasing population in the region is, in fact, a threat to the native indigenous population. All the new people coming from other parts of the country are taking up the spaces used by the natives. Urbanization and industrialization are eating up the Papuan rainforest and limiting the living spaces of the native tribes.
Despite its negative impact, we cannot simply shut down the Grasberg Mine. Grasberg is responsible for 93% of the gross domestic product (GDP) in the Mimika Regency and 32% of the Papua province. This signifies that a discontinuation in the Grasberg operation would take away 93% and 32% of the local and provincial economy respectively. The employment of 18,000 people depend on the Grasberg operation, without it 18,000 people will not earn any income, therefore, they would not be able to spend any money, therefore, other businesses will go bankrupt since nobody is buying their goods and services, therefore, ruining the economy of the Mimika Regency and Papua.
We can now see that the Grasberg Mine is not just a mine, but an important asset for both Freeport and the local community. The overall economical effect of the Grasberg Mine in a local scale seems to be as positive as it can get. Not just in Papua, all around the globe, the mining industry plays a vital role in the development of a region and its economy.