Triggers and Causes of the Landslide in Itogon, Benguet

by Philippine Resources - March 18, 2019

By Marcelle P. Villegas

September 2018 was a tragic, difficult month for the Philippine mining industry because heavy rains resulted in landslide in the Mountain Province region. Several small-scale miners died during the landslides in Itogon, Benguet. Other than being part of the headlines at that time, it also placed the mining industry under scrutiny or even misjudgment by many. What are the possible causes of the landslides? Is mining responsible for this incident? How can the science experts help in preventing this incident from happening again?

During the GeoCon 2018 last December, a study was presented with the title “Landslides in Itogon, Benguet: The triggers and Causes” with authors M. Madrigal, L. Manzano, R. Agot, et al. From their study and through investigation, this is what happened that day.

It was around 1:00 in the afternoon on 15 September 2018 when a small-scale mining community in Sitio First Gate, Barangay Ucab, Municipality of Itogon was devastated by a massive debris flow. The study reported that the debris materials originated from the northwestern slope of a ridge that was composed of highly weathered, altered and fractured diorite, andesite and pyroclastic rocks. At the western side of the slip, there was a high discharge flow of a creek, a tributary of Liang River. This aggravated the ground failure.

“It pushed the the debris flow materials farther towards the chapel and portal of an old tunnel level 070 of Benguet Corporation,” according to the report. The debris flow affected around 2.0 hectares downslope. There were other areas that also experienced massive landslides like the following barangays: Ampucao, Loacan, Gumatdang, Poblacion, Ucab and Virac.

It was reported that 87 people died and 12 were missing (DILG-CAR) as of 29 September 2018. Based on the rainfall data of PAGASA, the Province of Benguet received 250.2mm and 535.6mm of rainfall within 24 hours that was caused by Typhoon Ompong on September 14 and 15 respectively. Normally, there is a 10mm threshold for ground failure/mass movements to occur.

The study of this incident was conducted by having a methodology that employed anecdotal accounts, geological and geohazard assessment, Ground Penetrating Radar (GPR) Survey and drone mapping. The technical team from Mines and Geosciences Bureau-Central Office and Regional Office - Cordillera Administrative Region (CAR) conducted a delineation of critical areas/danger zone and assessment of small-scale mining communities.

The results revealed that the debris flow in the barangays are natural phenomena that was triggered by abnormally heavy rainfall that affected critical slopes underlain by highly fractured, altered and weathered rocks. GPR images also revealed that the areas are unstable and not suitable for permanent habitation and other developments. Moreover, the landslide incident were enhanced by human activities like removal of forest vegetation, small-scale mining operations, and development along unstable slopes and on ridges.

Findings and observations:

1) Rainfall

2) Geology and Geomorphology

3) Anthropogenic processes

Recommendations:

1)The team strongly recommends for the immediate relocation of small-scale mining communities away from areas delineated in critical zone with active landslides.

2) The concept of Minahang Bayan may be applicable in some areas but permanent habitation or settlement within the area of mining operation should not be allowed. Illegal mining should be stopped.

3) LGU to provide alternative and stable source of living for small-scale miners.

4) Consider expert opinion of geotechnical engineers along with in-depth studies in finding appropriate relocation sites.

5) Fault or lineament map of DOST-PHIVOLCS should be considered in the identification of relocation/settlement sites.

6) Warning signs should be installed along all road sections that were affected by the recent landslide.

7) Abandoned tunnels by small-scale mines should be backfilled immediately.

8) Choked sections of river channels should be declogged soonest to prevent artificial damming.

9) Prohibit slope loading by disposing muck or rock waste as well as heavy infrastructure development.

10) Revegetation of slopes is highly recommended.

Reference:

Mines and Geosciences Bureau, Department of Environment and Natural Resources

Acknowledgement:

Atty. Fernando Penarroyo, Geological Society of the Philippines


Place your Ad Here!


Related Articles

Company

Philippine Resources - January 21, 2021

TVIRD-Agata COVID-19 Response Brings Relief to 10,000 Families, Livelihood to Rural Farmers

At the height of the COVID-19 pandemic in the Philippines – that brought the nation’s economy to a virtual standstill and left thousands confined to hospitals, stricken with the deadly virus – communities in Mindanao have benefitted from an unexpected partner that immediately and actively responded to the government’s call to unity: and that is the country’s mining industry, which continues to support countrywide development.As of this writing, the industry has realigned some Php247 million of its collective Social Development and Management Program (SDMP) funds to provide relief for thousands of Filipinos in and around mining communities and close to 70,000 frontliners across the country.Immediate responsePrior to the realignment of SDMP to support relief operations, TVIRD’s Agata Mining Ventures Inc. already dispatched various Personal Protective Equipment (PPEs) from Manila as part of its immediate response to the needs of medical frontliners in the Mindanao region. TVI Resource Development Philippines Inc. (TVIRD) has facilities in Siocon, Zamboanga del Norte; Bayog, Zamboanga del Sur; and the adjacent municipalities of Tubay, Jabonga and Santiago in Agusan del Norte Province where its Agata Nickel Project is located.To date, the TVIRD Group of Companies has shored-up critical PPEs: N95 face masks, face shields and surgical and examinations gloves to support COVID-19 frontliners, including LGUs, volunteers, medical workers, police and civilian volunteers as well as checkpoint personnel. It likewise sourced majority of its fresh vegetable from farmers and other goods from local establishments to provide relief to more than 10,000 families in its respective areas. The group’s joint relief efforts aim to cushion the impact of the COVID-19 pandemic and has reached some 46 barangays consisting of its primary and secondary communities.Supporting local livelihoodWhile an estimated one million jobs have been “lost” as a result of the nationwide community quarantine, the challenges of a lockdown are even more pronounced in the hinterlands where a single day of lost livelihood can make or break agricultural and fishing communities who rely on their daily access to the market place. This is in addition to the challenge of putting food on their own tables for their families everyday.Agata sought to bridge this need by sourcing organic vegetables from its TESDA-certified Mabakas Farm School and its graduates under the program. Together with its beneficiary farmers, locally-sourced ampalaya (bitter gourd), kalabasa (squash), okra, sitaw (string beans) and eggplants were included in relief packs – which were distributed to 2,647 families in its three host municipalities.Recipients also included the company’s employees in the mine site and the indigenous Mamanwas who are themselves farmers who would have otherwise faced the risk of spoilage of their produce due to ECQ restrictions on transportation. Over 11,000 kilos of assorted vegetables were included in more than 5,200 relief and vegetable packs distributed by the company – a testament that its production model under the Mabakas framework is sustainable. TVIRD likewise rolled-out a weeklong food distribution program and reached-out to almost 7,424 families in the Zamboanga Peninsula. The company’s site personnel and officers sought to alleviate the residents’ difficulties by providing rice, vegetables, canned goods and noodles.Special attention was also given to the elderly, pregnant women, and persons with disabilities (PWDs) since they are limited to their homes under the GCQ Protocol. Beneficiaries also include nearly 1,400 Subanen families and farmers from Bayog Municipality whose produce are included in the relief packs. Frontliners in Zamboanga PeninsulaThrough its Balabag Office, TVIRD contributed several boxes of PPEs to major government hospitals, rural health units and birthing clinics in the Zamboanga Peninsula region.Beneficiary institutions include the Zamboanga Sibugay Provincial Hospital, Wilfredo C. Palma Memorial Hospital in Diplahan, Rural Health Units (RHU) in the joint provinces, Zamboanga del Sur Provincial Hospital in Pagadian City, and Siocon District Hospital – which also serves patients from its 26 barangays and nearby Sirawai and Baliguian towns.“TVIRD backs the government’s campaign against the disease. We are one with the frontliners – and providing them with protection and food is our way of sharing their load,” said TVIRD Balabag Project Manager Engr. Hilario Gingo, Jr.As the first company to be licensed under the Philippine Mining Law, TVIRD established its presence in the Zamboanga Peninsula some 25 years ago and has since fostered a deep relationship with its communities, especially the Subanon and Subanen tribes. The commercial operations of Agata marks the third consecutive project that TVIRD brought on-stream in a period of 10 years. Today, TVIRD-Agata has cultivated strong and resilient communities, self-sustaining indigenous hosts tribe and over 1,300 graduates from its Mabakas Organic Farm School who are aligible for TESDA National Certification.“‘Starting it right and keeping the end in mind’ has guided the company in achieving sustainable operations focused on progressive and final rehabilitation. By providing skills and infrastructure, we endeavour that our communities can sustain themselves beyond the life of the mine,” according to Agata Assistant GM Anthony Quijano.

Company

Philippine Resources - January 21, 2021

Taganito Mining Donates 7k Workbooks for Surigao Del Norte

As part of its commitment to support the education sector, Nickel Asia Corporation subsidiary, Taganito Mining Corporation, donated 7,172 workbooks to the provincial government of Surigao del Norte, in time for the opening of classes. The Php 2 million worth set of English and Mathematics workbooks is part of the company's Social Development and Management Program. The turnover of workbooks was led by TMC Resident Mine Manager Artemio Valeroso in the presence of Governor Francisco Matugas and Dr. Nelia Lomocso, the schools division superintendent of the Department of Education for Siargao, Surigao del Norte Division. In a certificate signed by Gov. Matugas, he thanked TMC “for the wholehearted support in the various undertakings of the Provincial Government which has been instrumental in the success of the Education Caravan School Year 2020-2021”.“NAC-TMC is one with the province of Surigao del Norte in helping our schools become ‘back-to-school ready,” said Valeroso“We are very happy and very thankful. We sincerely thank the Taganito Mining Corporation for this great donation. This will go a long way. The workbooks will be for the benefit of our learners in the island paradise of Siargao,” Lomocso said. Since 2015, TMC has been a partner of the province in the annual Education Caravan wherein various educational supplies such as books, bags, and health kits were distributed to students in Surigao del Norte as well as Siargao island.

Mining

Marcelle P. Villegas - January 29, 2021

Rare blue agate from Brazil with the face of Cookie Monster

A rare piece of volcanic agate rock was discovered in the Rio Grande do Sul region near Soledade in Brazil last November 2020. It is an oval-shaped rock with a hard, white pitted outer shell. On the outside, it looks like a perfect egg. When you split the rock at the center, you will see in each of the two halves a strange resemblance of Cookie Monster, a character from the famous children’s television show “Sesame Street”.[1] At first look, the rock’s photos and video which went viral on the internet seems surreal, but it is actually a unique piece of rock that was naturally formed in a volcanic environment, according to its owner. The rock is a deep blue quartz crystal and was discovered and found by Lucas Fassari, a gemologist and explorer in Brazil. [2][3] It was sent to Mike Bowers in California. Bowers is an American geologist and specializes in these types of rocks. He said that it could be worth as much as $10,000 due to its rare features. [1] Bowers uploaded on his personal social media account a video of the rock with the caption “Cookie Monster agate from Brazil” with a background music of Cookie Monster singing about the letter “C”. His post immediately became viral online. The actual cost of the rock when bought from Fassari was not revealed by the current seller. [3] “I think this is probably the most perfect Cookie Monster out there. I have seen others but here you have it complete on both sides. This is very unusual. There are a few famous agates out there: the owl, the scared face. There are many approximate ones but it is rare to find one so well defined like this,” Bowers said. “Prices can be very high. I was proposed over $10,000 by five different buyers. Rare.” While his viral video of the Cookie Monster agate is fascinating, it also brought some doubt to most people. Is it really possible for nature to produce a semiprecious stone with such strange appearance? What are agates and how are they formed in the first place? Geology.com described the agate as a translucent variety of microcrystalline quartz. It is formed by the deposition of silica from groundwater in the cavities of igneous rocks. Agates are formed by the deposits of silica from groundwater in the cavities of igneous rocks. The agate deposits in concentric layers around the walls of the cavity or in the horizontal layers building up from the bottom of the cavity. As a result, layered patters are then formed. In some agate formations, these cavities are lined with crystals, therefore called geodes. A geode is a round rock with a hollow space lined with crystals, just like the Cookie Monster agate. Agates come in a wide range of colours such as brown, red, yellow, gray, black, pink and white. The colours are produced by the impurities during its formation and they are formed in alternating layers within the agate. Now, the variations in colours are produced once groundwater of different compositions leak into the cavity. The banding within a cavity is a manifestation of change in water chemistry. As an end result, agates end up having interesting colours and patterns. Based on this general description of agate, the authenticity of the Cookie Monster agate seems legitimate. Bowers reported to Daily Mail UK that the rock is indeed real. [1] A fact-checking website, Snopes.com. also claimed that rock is authentic. [3] TechnologyTimes.pk on the other hand stated, “As of the moment, there are no news yet as to whether Bowers actually intends to sell the rock or not, and about its current value as of the moment. Furthermore, no authorities have confirmed whether the rock is real or fake. If it is, sure enough, its value will increase over time as more and more people take interest in the unusual rock. Who would’ve known Cookie Monster would make so much numbers in a rock?” (--Marcelle P. Villegas, PRJ) Reference: [1] Boyle, Darren (19 Jan. 2021). Daily Mail UK. "What a muppet! Geologist finds incredibly rare lump of volcanic agate rock which looks exactly like Sesame Street's Cookie Monster". Retrieved from - https://www.dailymail.co.uk/news/article-9162441/What-muppet-Geologist-finds-rock-looks-like-Sesame-Streets-Cookie-Monster.html [2] Hart, Matthew (26 Jan. 2021). Nerdist. "Gemologist Cracks Open Rock, Finds Cookie Monster's Face". [3] Evon, Dan (26 Jan. 2021). Snopes. "Is the 'Cookie Monster Rock' Real?". [4] Noor, Mufliha (25 Jan. 2021). Technology Times.pk. "'Cookie Monster' Rock From Brazil: Real or Fake?".

Place your Ad Here!

Place your Ad Here!


Recent Articles

Mining

Philippine Resources - August 05, 2022

NICKEL ASIA CORPORATION ANNOUNCES P3.83B NET INCOME FOR H1 2022, UP 41% YoY

Photo Credit: Arrow Creatives Nickel Asia Corporation, the Philippines’ largest producer of lateritic nickel ore, reported a 41-percent increase in attributable net income for the first semester this year. Based on unaudited financial and operating results for the six-month period ended June 30, 2022, attributable net income increased to P3.83 billion from P2.73 billion while earnings before interest, tax, depreciation, and amortization (EBITDA) increased by 19 percent to P6.33 billion from P5.32 billion the year prior. Despite lower ore volume sold during the period, revenues increased by 7 percent to P11.78 billion from P11.01 billion last year, owed largely to higher nickel ore prices and favorable exchange rates. NAC’s four operating mines sold a combined 6.95 million wet metric tons (WMT) of nickel ore during the first half of the year, down 16 percent from 8.30 million WMT in the same period last year. The drop in sales volume was almost in direct proportion to unrealized workable days caused by inclement weather that adversely affected the Company’s mining operations during the period. The weighted average nickel ore sales price over the first half of year 2022 rose by 18 percent to $30.03 per WMT against $25.54 per WMT in the same period last year. The Company also realized P52.56 per US dollar from these nickel ore sales, a 9-percent increase from P48.25 last year. Breaking down the ore sales, the Company exported 3.12 million WMT of saprolite and limonite ore at the average price of $42.05 per WMT during the six-month period compared to 4.55 million WMT at $37.62 per WMT in the same period last year. Likewise, the Company delivered 3.83 million WMT of limonite ore to the Coral Bay and Taganito high-pressure acid leach (HPAL) plants, the prices of which are linked to the London Metal Exchange (LME) and realized an average price of $12.52 per pound of payable nickel. This compares to 3.74 million WMT at $7.92 per pound of payable nickel in 2021. Expressed in US dollar per WMT, the average price for the deliveries to the HPAL plants were $20.23 and $10.85 in the first half of 2022 and 2021, respectively. “The first half of 2022 was not without its challenges especially for our mining operations, brought about by weather conditions at our mine sites, particularly in Surigao, and continuing lockdowns in China, our major market,” said Martin Antonio G. Zamora, President and CEO. "However, the higher LME nickel price and stronger US dollar tempered the impact on our revenues.” Owing to the higher LME nickel price during the period, NAC also recognized gains from its equity share in investments in the two HPAL plants in the combined amount of P1.09 billion against P244.1 million year-on-year. The stronger US dollar further enabled NAC to log a 353-percent hike in net foreign exchange gains from its foreign currency-denominated net financial assets to P863.5 million from P190.6 million the year prior. Total operating cash costs decreased by 2 percent year-on-year to P5.19 billion from P5.32 billion last year. On a per-WMT sold basis, total operating cash costs increased to P747 per WMT compared to P641 per WMT in 2021. For the Company’s renewable energy business, its subsidiary, Emerging Power, Inc. (EPI) energized in June 2022 another 38-megawatt (MW) solar farm in Subic, Zambales, bringing total capacity on this site to 100MW. For 2022, the Subic plant has been operating at an 18- 19% plant efficiency factor with 90% of generation contracted under power sales agreements. EPI has realized an average tariff of P4.65 per kilowatt hour. EPI has another 100MW service contract for the Subic site and will commence construction of a 68-MW farm in August. Completion is expected by the third quarter of next year. EPI was also chosen by Shell Overseas Investments B.V. to be its exclusive local partner in a solar, onshore wind, and battery storage joint venture that aims to contribute up to 3GW into the Philippines’ renewable capacity. NAC is evaluating a range of financing alternatives including accessing global debt capital markets to raise EPI’s share of the equity required for an initial 1GW target by 2028, among other uses. The Company’s strong financial position will allow it to be opportunistic in evaluating funding options that meet the primary objective of maintaining a flexible low-cost capital structure. “We remain confident that our mining and renewable energy businesses provide a solid foundation on which to realize the OneNAC Vision’s twin objectives, which is to become the premier ESG investment in the country and to be counted among the Top 25 PSE-listed companies in terms of market capitalization by 2025,” said Zamora.   Article courtesy of the Philippine Stock Exchange

Mining

Philippine Resources - August 04, 2022

Further shallow copper mineralisation identified at MCB

Figure 3. Cross section of drill hole MCB-039 relative to the interpreted geology and significant assay results. We (Celsius Resources) are pleased to announce we have received further shallow and high-grade copper assay results from the ongoing drilling program at our flagship MCB copper-gold project, held under our Philippine subsidiary Makilala Mining Company, Inc. (“MMCI”).  The results continue to identify new positions of shallow mineralisation which are in line with other recent drilling results from holes MCB-036, MCB-037 and MCB-038 (see CLA announcements dated 13 December 2021, 23 May 2022 and 4 July 2022 respectively) confirming the presence of an extensive shallow higher-grade position.  The results from MCB-039 were designed to further expand the size of the shallow higher-grade copper zones which are considered to have an important positive impact on early mining options at MCB. The current drill hole in progress (MCB-040) is similarly designed to further expand the higher-grade copper mineralisation leading to potential improvements to the economics of the already positive Scoping Study at MCB as reported by Celsius on 1 December 2021. “The results from MCB are continuing to grow the size of the shallow higher-grade copper zones,” said Country Operations Director, Peter Hume. “We are getting much better definition now on the various high-grade zones, which are important for the optimisation of the MCB mine plan. We can see many good high-grade intersections coming together to expand on the earlier understanding of these high-grade zones. Where we get multiple high-grade zones staked on top of each other, we can achieve outstanding results, as recently announced from hole MCB-038 which intersected 611.4m @ 1.39% copper and 0.75g/t gold from 32.5m.” RESULTS FROM MCB-039 Drill hole MCB-039 was drilled to further confirm the interpretation that further shallow high-grade positions exist as a relatively flat body extending into the surrounding host rocks (see Figures 2 and 3). This drill hole was more specifically targeted to fill a gap in the drilling information where there was previously defined lower grade copper mineralisation. The results from MCB-039 have confirmed the further extensions to the higher-grade copper mineralisation as part of a series of relatively flat lying, high-grade zones which are extending away from vertically orientated feeder structures which are all closely related to an intrusive Tonalite rock (Figure 3). Figure 2. Location of MCB-039 drill hole relative to recent and historical diamond drilling at MCB.​​​​​ A large broader envelope of copper mineralisation at a lower cut-off grade at approximately 0.2% copper also continues to be better defined, highlighting the very large scale of the copper-gold mineralisation at the MCB deposit. Table 1: Significant intersections from drill holes MCB-039.   Article courtesy of Celsius Resources. Full press release can be found HERE

Mining

Philippine Resources - August 04, 2022

Diokno banks on mining for sustained economic recovery, expansion

Photo credit: PNA - Finance Secretary Benjamin Diokno Finance Secretary Benjamin Diokno said the mining industry is a potential source of sustained economic growth as he underscored the benefit of mobilizing investments for mine development. “The mining industry holds the greatest potential to be a key driver in our economic recovery and long-term growth, especially now that world metal prices are high. The Philippines, after all, is one of the world’s most richly endowed countries in terms of mineral resources,” he said Wednesday at the listing of Philex Mining Corporation’s (Philex) common shares in the Philippine Stock Exchange (PSE). Philex is mobilizing investments for the development of its Silangan underground copper-gold mine in Surigao del Norte. In a disclosure to the PSE, the company said it is offering a maximum of 842 million common shares at the rate of one offer share for every 5.8674 shares owned for PHP3.15 each to raise a total of PHP2.652 billion new equity. The stocks rights offering (SRO) period started on July 12, 2022 and ended July 25, 2022. The Silangan project, considered one of the biggest copper-gold mines in the country, is planned to be mined in two phases. The first phase has a mineable ore reserve of 81 million metric tonnes which will be mined for 22 years at a rate of 4 million tonnes per year. The mine is targeted to commence commercial operations in the first quarter of 2025. Diokno said Philex’ SRO listing demonstrates the mining industry’s confidence in the country’s promising economic growth prospects.   He said the offering means more jobs will be created, local economies will be reinvigorated, and additional revenues will be contributed to the government.  The Department of Finance (DOF) estimates that the project will generate around PHP8.5 billion in excise taxes alone for its entire mine life. Diokno said the listing sends a strong signal to the mining industry that the country's capital markets are viable instruments for fast tracking the development of large mining projects.   He said the Marcos administration is committed to continue creating an enabling environment for mining activities to flourish in the country as he looks forward to similar listings in the future. “We recognize that apart from boosting local development, mining is a strong magnet for investments that can propel our economy into a higher growth trajectory,” he added. Diokno said the government expects the mining industry to strictly adhere to responsible and sustainable mining practices.  He said the mining industry should strike a balance between protecting the environment, uplifting local communities, and supporting the government’s socioeconomic agenda. “This is a non-negotiable condition so we can guarantee the sustainability of the industry and the strong economic growth of its host communities,” he said.    Article courtesy of the Philippine News Agency

Place your Ad Here!

Join the Philippines'

Mining and Construction Community

Be the "First" to get our exclusive Digital Magazine & Newsletter.