A Study on Philippine Geosources: Silver in Compostela valley
Group 4, STEM 11K
Chua, Katrina Lorraine C.
Cue, Ryan Daniel A.
Lim, Sean Lloyd T.
Villafuerte, Matthew A.
Abstract
Introduction
Description of the study site
The province of Compostela Valley is a rich mining ground in Mindanao. In Mt. Diwata is a rich gold ore deposit. Alongside the mining of gold is the mining of silver, which is a by-product of gold.
The province of Compostela Valley is in mid-eastern Mindanao. It is bounded by Agusan Del Sur on the North, Davao Oriental on the East and South, Davao Gulf on the Southwest, and Davao Del Norte on the West and Northwestern portion. It has a land area of 4,667 square kilometers. There are 11 municipalities comprising the province, with Nabunturan as the provincial capital. (Philippine Information Agency, 2018)
Compostela Valley is a work of art. It has a lot of natural attractions like beaches, waterfalls, forests, mountain ranges, caves, lakes, rivers, hot and cold springs, all found in the province, which makes it a strong tourist spot in Mindanao. (Guia, 2012)
The highest elevation in the province reaches a height of more than 2,000 meters above sea level (MASL), and this is found in the municipalities of Maragusan, New Bataan and Pantukan having a combined area of 80.89 square kilometers or 1.7% of the total land area of the province. The lowest elevation is at below 100 MASL with Laak having the widest area of 215 hectares while New Bataan with the narrowest of 19.10 sq. kms. Around 30% of the province total land area is characterized with 500-1000 MASL elevation of which all municipalities except Montevista (up to 300-500 MASL only) have areas within this elevation range. (Provincial Government of Compostela Valley, 2017)
The province has rich deposits of metallic and non-metallic mineral resources. Metallic resources include gold, silver, copper and iron among others with both large and small-scale mining operations present. Small-scale mining is more on gold and silver extraction and or exploration. The Diwalwal Mineral Reservation Area in Monkayo was among the five medium-scale operating gold mines identified in the country. (Provincial Government of Compostela Valley, 2017)
B. Demographics of the Study Site
According to the 2015 Census of Population and Housing (CPH), Compostela Valley posted a total population of 736,107 persons. This is larger by 48,912 persons when compared to total population of 687,195 in 2010 CPH. The increase in population count from 2010 to 2015 indicates an Annual Population Growth Rate (APGR) of 1.4%. This is slower by 0.33% of the APGR between 2000 and 2010 intercensal period. If the 1.4% APGR of the province will continue, its total population will double in the year 2065 or a doubling time of 50 years.
Nearly 73% or about 540,000 people reported Roman Catholic as their religion. The proportion slightly reduced as compared to 73.5% in the 2010 census. The next religious affiliation which has largest membership was the Evangelicals or the Philippine Council of Evangelical Churches with 8.3%.
“Cebuano” or “binisaya” is commonly spoken by around 31% of the province’s populace. Others speak boholano, Hiligaynon/Ilongo, Tagalog and native dialect of mansaka and mandaya. Of the household population in Compostela Valley, 31.7% reported Cebuano as their ethnicity. This means that 3 in every 10 persons in Compostela Valley are Cebuanos. Other enthnic groups are Bisaya/Binisaya (19.7%), Boholano (14.8%), Mansaka (6.8%), Hiligaynon/Ilonggo (6.1%), Mandaya (5.8%), Dibabawon (2.4%), Waray (2.2%), Ilocano (1.8%), Davaweño (1.5%), and others.
Figure 1 below shows that the Annual Population Growth Rate (APGR) of the province based on the four censuses conducted in 1990 to 2015 is decreasing from 2.21%in 1990-2000 intercensal periods to 1.32% in 2010-2015 intercensal periods. This means that from about 2 people’s annual increase for every 100 populations from year 1990 towards year 2000, it decreased to about 1 person annual increase for every 100 populations from year 2010 towards year 2015.
Of the 734,402 household populations in 2015, males accounted for 52.4% while females comprised 47.6%. Among the component 11 municipalities of the province, Pantukan has the largest male-female ratio of 115 males for every 100 females, higher by 5 male individuals than the provincial average, while Compostela and Mawab have the least male-female ratio recorded at 107 males to 100 female. The 2015 CPH showed that around 34 out of 100 people or 33.64% are below 15 years old. Children aged 0 to 4 years and 5 to 9 years (11.35% and 11.36%, resepectively) comprised the largest age group, followed by those in the age group 10 to 14 years (10.9%) and 15-19 years (10.03%). Males outnumbered females in the age groups 0 to 69 years, while females outnumbered males in the age group 70 years and over. This implies that females live longers than males. (Provincial Government of Compostela Valley, 2017)
C. Objectives of the study
This study of the mineral silver located in Compostela valley aims to find answers for the following objectives:
To Know how much silver is within Compostela Valley
To Discover how do these resources form
To learn what are the benefits of this resources
To learn how to obtain/extract these resources
To know if we are using these resources efficiently
To know what are the risks involved in using and extracting these resources
To know what happens if these resources run out
To find a balance between economical development and environmental protection
Distinct Mineral Profile
A. Name, Image and Chemical Composition175704525146000
The name of the Mineral is silver its Chemical formula name is Ag.. It can also be mixed with other elements like Gold, Arsenic, Mercury and antimony. Its Chemical Formula varies from (Ag,Au);(Ag,Au,Hg,As,Sb).
Amount and Economic Value
Formation
D. Extraction Process
Silver is extracted from the ore-argentite (Ag2S) and there are multiple ways in extracting this mineral. One way is using the cyanide process having sodium cyanide solution a main factor in this method. Another method is the flotation process where most silver bearing minerals would float together with their base minerals
Using the cyanide process, the ore is first crushed, usually with 1-1.5 in (2.5-3.75 cm) diameters, to make the material porous. Approximately 3-5 lb (1.4-2.3 kg) of lime per ton of silver ore is added to create an alkaline environment. The ore should be free of any sulfide minerals, so the process of oxidation is needed to be done.
Where fines or muds exist, the mineral is gathered into a cluster to make a uniform drain heap. This procedure consists of smashing the metal, including bond, blending, including water or a cyanide arrangement, and restoring in dry air for 24-48 hours.
Two Broken or squashed metal is stacked on impermeable cushions to dispense with the loss of the silver cyanide arrangement. Cushion material might be black-top, plastic, elastic sheeting, as well as muds. These cushions are inclined in two ways to encourage waste and the accumulation of the arrangements. Water and sodium cyanide are added to the metal. Arrangements are conveyed to the loads by sprinkler frameworks or techniques for ponding, including trench, infusion, or drainage from vessels (refer to figure 1). (“How silver is made – material, making, history, used, processing, industry,” n.d.)
Figure 1
cyanide leeching process (n.d) Retrieved from http://www.madehow.com/Volume-3/Silver.htmlAnother procedure in obtaining silver is called as the Silver flotation process. It is mainly applied for the recovery of silver and associated metallic minerals, silver including two categories: one is silver &gold, the other is copper, lead, and zinc associated. (“Silvermine, Extraction of Silver, Silver Recovery, Silver Flotation Process – Xinhai,” n.d.) By using the process of flotation, the most common silver-bearing minerals that can be recovered are argentiferous galena, native silver, argentite (Ag2S) and tetrahedrite (Cu, Fe, Ag) Sb4S3 (“Silver ores,” n.d.). The minerals would float together with their base minerals like copper and lead sulphide or even tetrahedrite which is the primary target mineral. It is best for silver minerals to be at natural PH when flotation response due to lime depressing silver minerals in flotation. Soda ash is suggested to be an alternative Ph modifier when the Ph levels need to be increased. When high silver mineral selectivity is required, Alkyl dithiophosphates are used (“Silver ores,” n.d.). One can also recover silver values when normal flotation practices used in floating specific sulfides is used when the silver is associated with metal sulphide minerals.
E. Use/ applications
Silver can be found and used in a lot of things. The biggest user of silver compounds is the photography industry. To develop high-quality photography, silver nitrate is needed because it forms the most light-sensitive salts called as halides. The sectors in the industry that uses silver includes consumer photography, graphic arts and radiograph (x-rays) in medicine and industrial inspection of heavy machinery (“What is silver used for in industry? | BullionVault,” n.d.).
If the biggest user of silver is the photography industry, the most common application of silver is in the jewelry and silverware industry. Silver plays a vital role in their livelihood. The most common silver used for jewelry making and silverware is Sterling silver, mixed with 5-20% copper in alloy. Pure silver is not advisable to be used since it is too soft to be durable. Silver’s brilliant reflectivity, shiny luster, and durable frame when alloyed with copper, made it possible for it to be used in items such as utensils, dishes, silverware, jewelry like rings, necklaces, bracelets, ornaments and more since at least the 14th century.
In Field of Photovoltaics nowadays, silver is one of the minerals that is pursued in the energy market due to the advancement in solar panel technology. Each year its use is growing rapidly. Just since 2000, the amount of silver consumed by solar-panel makers has risen an average of 50% per year. Demand grew from one million ounces in 2002 to 60 million ounces in 2011. In 2011, demand from the PV industry represented almost 11% of total industrial demand for the metal (excluding jewelry). According to statistics from CPM Group, demand grew by 11.2 million ounces, the strongest volume growth of all major sources (jewelry and electronics). And this was before the Japanese announcement was made (refer to figure 2) CITATION The1 l 13321 (The solar silver thrust, n.d.). Solar panels these days are using photovoltaic cells that can convert sunlight into electricity at the atomic level. These photovoltaic cells or light photons transform electrons into direct current carriers. With silver, it can be printed onto the cells to carry the current because silver is conductive. Silver also benefits the electronic industry since it can be used in electronics such as computers, keyboards, televisions, cellphones, microwave ovens, calculators, etc. It also can be used for coating for CDs and DVDs.
Figure 2
Data on the demand of silver from the soar panel industry (Casey research, 2012), Retrieved from http://www.mining.com/web/the-solar-silver-thrust/In the chemical process industry, silver is used as a catalyst since it is one of the strongest oxidants. It is used in the production of adhesives, dinnerware, mylar recording tape, and used in x-ray vacuum tubes as a material for bearings. Silver also has the highest level of thermal conductivity among metals, resistant to combustion and to sparks making it a good material for many other industrial processes.
The glass industry also benefits silver. In making mirrors, a micro-thin layer of a silver nitrate is sprayed on treated glass to create the reflective surface. 90-99% of harmful UV rays bounce off glass coated with silver. With silver coating on glass, it can help in protecting the eyes, driving safely, and protecting from the sunlight shining from windows.
Silver contains antibacterial activity that makes it as a distinguished tool ins sterilization. Doctors, and those who work in the medical field benefit silver since it is a necessity in their field. Without the use of silver, saving a patient’s life would be difficult. It can help in killing anti-biotic resistant MRSA. (“Silver as an Antimicrobial Agent – microbewiki,” n.d.) It is used for wound dressings, endotracheal tubes, surgical masks, cotton fibers, burn treatments, catheters, prosthetics, dental fluoride & fillings, surgical needles & sutures, hearing aids and so much more.
Based on its low known toxicity to humans, silver has been suggested as a possible disinfectant of drinking water (Silvestry-Rodriguez et al., 2007). Water purifying companies are starting to switch to the use of silver rather than of chlorine which can form many hazardous compounds. The use of silver for drinking water treatments has already been successfully used in the United States and Water recycling systems on the Mir space station and NASA shuttles have used silver as an effective water disinfectant.
Risk involved
In the use/ extraction
In depletion
Others
Discussion
Conclusion
References
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