Department of Environment and
Natural Resources
Mines and Geosciences Bureau
13TH ANNUAL FORUM
November 14 – 15, 2003
ABSTRACTS
SPECIAL PAPERS
Surface and Shallow-Surface Structural Observations in the Ortigas Area:
Implications
for Earthquake Hazards in Metro Manila
Dr.
Mario.A. Aurelio
Urban
Geology Section, Lands Geological Survey Division
Mines and Geosciences
Bureau, North Avenue, Diliman, Quezon City
Geologic structures observed in excavations and surface exposures of the
Diliman Tuff Member of the Guadalupe Formation in and around the Ortigas Centre
(Pasig-Mandaluyong area) located about a kilometer or less west of the mapped
trace of the West Valley Fault (WVF), are analyzed in the context of fault
generation and its implications to the assessment of earthquake hazards in the
metropolis. Fault populations generally strike NNE to NE with steep dips
(70°-80°) dominantly directed to the SE. Some fault surfaces show
well-preserved slickensides indicating clear strike-slip as well as normal
movement. Normal faults show significant vertical displacements that, if
related to earthquakes, suggest moderate to high magnitudes. Although such
faults are observed to traverse through the surface, the absence of recent
datable surficial deposits hinder constraining their ages.
Phase 2 MGB-Central Office Networking Project
Rolando M.
Fernandez
Mineral
Rights Management System Section
Mining
Tenements Management Division, MGB C.O.
The ultimate goal of the MGB
Networking Project is the establishment of communication and information
connections that leverage computer technologies, which one way or another
achieve MGB’s vision and mission as a line bureau of the Department of
Environment and Natural Resources.
In
retrospect, phase 1 of the Project encompassed eleven (11) network nodes in
peer-to-peer configuration and following IEEE
803.2 or Fast Ethernet network standard with a maximum bandwidth of 100
Mbps. The network spreads over the J.C.
Fernandez Bldg. of MGB-CO compound. Two
floors (2nd and 3rd floor) of the building have been
connected in the network backbone.
Phase 2 of the project seeks the full cabling of the J. C. Fernandez
Building.
From Phase
1, lessons have been learned in achieving network connectivity in the face of
constraints in hardware and software resources because of budgetary
constraints. Appropriate open source
softwares have been utilized for the project.
Overall,
the MGB network is evolving and attendant issues in regard to its
current/future design, administration and maintenance will be discussed.
Geological Considerations for the Siting of a Repository
for Low and
Intermediate-level Radioactive Waste (LILW) in the Philippines
M.A.
Aurelio1, E.M. Valdezco2, E.B. Aguinaldo1 and
the
Philippine
Inter-agency Committee for Radioactive Waste Management3
1Mines and
Geosciences Bureau, North Avenue, Diliman, Quezon City
2Philippine
Nuclear Research Institute, Commonwealth Avenue, Diliman, Quezon City
3PNRI-DOST,
DOE, NPC, DENR, DOH
Low- and intermediate-level radioactive waste (LILW) in the Philippines is
being generated essentially in hospitals, medical and pharmaceutical
institutions, isotope research laboratories, paper mills and other related
industries. International regulations as well as national legislation require
stringent specifications in the proper disposal of such waste. One such
requirement is the establishment of a permanent repository in accordance with
guidelines set by the International Atomic Energy Agency (IAEA). At present,
the Philippine government, through an inter-agency committee on radioactive
waste management spearheaded by the Philippine Nuclear Research Institute, DOST
(PNRI), is currently undertaking an IAEA-funded project on the site selection
and conceptual design of a near surface LILW disposal facility. The Mines and
Geosciences Bureau, DENR (MGB) is tasked to undertake studies in geology which
is an important component of the study, among many other fields. This paper
tackles some of the more important considerations from the geological
standpoint.
“A
Multi-sectoral Approach to Elimination of Child Labor in
Small Scale Mining in the Camarines Norte Experience”
Elsa D,
Rejoso, Ph.D.
Senior
Science Research Specialist
and
Reynulfo A.
Juan
Regional
Director
MGB R-V
A three-year program aimed at combating child labor (CL) in small-scale
mining with funding from the Government of Finland was implemented in six
small-scale mining villages in the municipalities of Labo, Paracale, Jose
Panganiban, Camarines Norte from June 2000 to May 2003. It was carried out thru
the overall supervision of the International Labor Organization-International
Program for the Elimination of Child Labor (ILO-IPEC) with different government
agencies and non-government organizations as implementers of component action
programs. Strategies of the program include two broad areas of action: a)
installation of social protective services to child workers and their families
and b) intensive capability building for policy and program implementers of a
child labor program in the province.
Specific project components that are geared towards prevention and
social protection of child labor as well as capability building was implemented
thru community organizing and empowerment, provision of education and
alternative livelihood, policy planning and research, program monitoring and
training of implementers.
Involvement of MGB-5 in the project was in the policy planning thru the
Provincial Mining and Regulatory Board (PMRB) wherein specific resolutions
prohibiting the employment of CL in small-scale mining were enacted. It has also
undertaken training for the different partner agencies/organizations on
environmental and safety concerns in SSM operations.
TECHNICAL
PAPERS
Generating Geohazard Maps
for the San Pedro-Cavite Quadragles
Based on a Multisource and Morphostructural Analysis
M.M.L.
Tumonong and C.J. Manipon
LGSD, MGB CO
In generating geohazard maps for northern Cavite and vicinity, a
multisource and morphostructural analysis was done. The various source
materials utilized include published reports, historical accounts, current and
old topographic and geologic maps, and aerial photographs. Resulting analyses
were then processed in a Geological Information system (GIS) platform. The
preliminary result of this study states that the study area is most vulnerable
to three major geologic hazards: hydrological, coastal, and seismic hazards.
Particular areas along the coasts of northern Cavite including Paranaque
City and Las Piñas perennially suffers from tidal flooding, as well as areas
along the lakeshore of Laguna de Bay. These same areas are also susceptible to
clogged drainages and seal level rise. Aggradation occurs in the southeastern part of the Bay, particularly from
Timalan River to the Cavite spit. On the other hand, the northwest-facing
coastline behind the spit exhibits natural progradation. In Laguna de Bay there
is widespread shoaling within the western and central lobes.
Digital terrain modelinh of northern Cavite and vicity reveals a
generally flat terrain with only 5% of the area exhibiting more than a six-(6)
degree slope. Deterministic ground acceleration modeling using the equation
proposed by Fukushima and Tanaka (1990) using the Marikina Valley Fault System
as earthquake generator at magnitude 7.5 shows the area to have high “g”
values. Using the same equation but with the Philippine Fault as the
earthquake generator at magnitude 8,
reveals generally low to moderate “g”
values for the area. Other seismic hazards in the area are ground
rupture and liquefaction. Historical accounts record a tsunami event in western
Cavite while other workers have also considered the possibility of seiches for
Laguna de Bay.
Slope Instablility and Hazard Zonation of
Baras Quadragles Using Geographic Information System
Fidel R.
Zepeda* and Arnold A. Villanueva**
MGB R-IV
Mass
movements and slope instability has been a familiar sight in Baras
Quadrangle. Using Geographic
Information System (GIS), such information were superimposed to several
existing maps to reveal their relationships to the slope gradient, geology and
structural conditions of the area.
Several thematic maps were produced and utilized to come up with a
generalized hazard map. Three (3)
hazard zones were deduced: (1) Zone 1 is represents a low hazard area where the
probability of occurrences of landslides are very limited even with strong
triggering factors, such as heavy rainfall and earthquake. (2) Zone 2 characterized the medium hazard
area wherein some mass movements will be generated under the influence of
intense triggering factors and (3) Zone 3 constitute a high hazard area where a
considerable number of mass movements will be expected even with the presence
of weak triggering factors.
Geological Assessment, Mine Evaluation, Planning and
Design of the
Feldspar Deposit in Laur, Nueva Ecija
Nelson D.
Quiwa, Vincent T. Lunar, Nixon R. Dalapus and Elanor T. Rivera
MGB R-III
Since 1992,
extraction of feldspar in Laur, Nueva Ecija has started supplying the biggest
tile manufacturers in the country like Mariwasa Manufacturing Co. and Lepanto
TileCo. Ceramic tile is composed of
about 40% feldspar and is used as a fluxing agent.
Laur, which
is considered as one of the remotest town of Nueva Ecoja is located on the
extreme eastern part of the province and lies on the western slope of the
Sierra Madre Mountains. It is also known for its is abundant source of feldspar
in the country. But due to the inconsistency of the quality of the feldspar and
poor access road, mining operation in the area is intermittent depending on the
demand from their prospective buyers.
Through a
Memorandum Of Agreement (MOA) with the Project Development Assistance Center of
the National Economic Development Authority R-III, a detailed geological
assessment, mine evaluation, planning and design study of the feldspar deposit
in Laur was conducted. The study
revealed a geological reserve of 166,545,073 metric tons and mineable reserve
of 104,328,945 metric tons covering a total area of 186 has. With an average
thickness of 37 meters. This can supply
the present demand of 250 tons per day for 816 years.
The feldspar deposit is underlain mainly by Barenas-Baito formation of
probable late Cretaceous in age and later intruded by the Bangco Diorite which
is considered the source of feldspar mineralization in the area. From the
megascopic, physical and chemical analyses, three type of feldspar were
identified: (1) feldspathic clay (2) reddish brown fldspar and (3) white
feldspar. Also, from the XRD analysis, quartz and plagioclase were detected
from the samples. The plagioclase feldspar in these samples is predominantly
albite or soda type of feldspar.
From the
analyses made, the feldspar deposit has been positively identified as raw
materials for tile making. Other applications of this feldspar are in the
manufacture of decorative ceramics such as terra cotta, earthware and
stoneware.
With the promising result of the study, it is recommended that
proper and safe mining method be
employed and mining operators be organized into cooperative. Once implemented, it is expected that the
project will generate jobs for the community and will generate revenues of the
local government.
Factors Influencing the Coastal Changes
Along the
Eastern Portion of Lingayen Gulf
Dominador C.
Punongbayan, Ramon V. Macabuhay, jr.,
Reynaldo l.
Villela, Leopoldo T. Virtucio
MGSD, MGB
CO
The coastal areas
are generally considered as the most dynamic and productive sites in terms of
living and non-living resources but unfortunately these areas are also regarded
as the most complex habitat system and the most susceptible to both natural and
man-induced hazards such as flooding, coastal erosion, siltation, pollution and
other coastal geoenvironmental problems. On this premise, field study and data
gathering were carried out in the coastal and nearshore areas along the eastern
portions of Lingayen Gulf in order to determine the factors and processes
bringing about coastal degradation and aggradation and the inherent coastal
changes.
Results of the study have shown the significant roles of waves, tides,
longshore current, climate and weather, geologic structures, lithology, tectonics, sea-bottom topography and
man-made structures in effecting coastal geomorphic changes in the study area.
Fossil Collections and Researches at the
Mines and Geosciences Bureau (MGB), Quezon City, Philippines
Yolanda
Maac-Aguilar
LGSD, MGB
CO
Fossil
collections at the Philippine Mines and Geosciences Bureau are dominantly
microfossils consisting of small and large foraminifers, radiolarians and
nannofossils. These are stores in
slides and blocks, are catalogued and are recorded in a computerized database
at the Paleontology Unit of this Office. Coral, brachiopod, crustacean, and
echinoid specimens are rather limited in number due to lack of experts who will
attend to these groups of fauna.
However, molluscan collections have significantly increased this year
because of the collarative efforts between the Bureau and the National Science
Museum in Tokyo, Japan..
Paleontologic
research in the Philippines was initiated by Antonio Francisco Llanos as early
as 1861 when he reported on the occurrence of Nummulites in the country. From
then on, intermittent reports were published on large Foraminifers, mollusks,
echinoids, other invertebrates and some vertebrates fossils.Leopoldo Fautino,
however, pioneered paloentologic research in the Bureau of Science (former
appellation of the MGB) in the mid 1920s when he discussed molluscan fossils
identified in some coal measures in the Philippines. The advent studies of
plantic foraminifers came in the later part of 1940s when search for oil and
gas was still mandated to the then Bureau of Mines. In the second half of the
1990s, paleontologic researches in this office temporarily lie dormant because
most of its staffs were sent abroad for advance studies and some were
reassigned to other offices of the bureau . At present, aside from the usual
biostratigraphic works., paleontologists have branched out to other fields like
paleobiogeography, taphonomy and paleoclimatology. Alsom due to the daunting situation of our ecosystem, living
organisms are presently being targeted in order to be attuned to the current
thrusts of the government to environmentally related researches.
Landslide Suceptibility
Zonation of Mt. Diwata, Monkayo,
Compostela Valley and Terrain Mapping of the Diwalwal Mineral Reservation
A.L.M.Fernando, F.C.
Jacoba, Jr., G.E.C. Bascos
Urban
Geology Section, Lands Geological Survey Division
MGB CO
This paper presents
the landslide hazard zonation of Mt. Diwata, Monkayo, Compostela Valley, a
mountainous gold-rich district where the Diwalwal gold-rush area is situated.
The present land-use practices and the current mining activities in the area
have greatly affected the stability of the slopes, thus aggravating the
problems on landslide hazards in the area. The landslide hazard zonation map
presented in this paper classifies the study area into three (3) zones with
respect to its susceptibility to landslide hazard. On the other hand, the
qualitative risk map shows the general relation between the hazard and
vulnerability of the population, which is in this case the element at risk
considered. The combination is done using a two (2) dimensional table. The
qualitative risk map generated primarily intends to show areas that would
require immediate attention so that action could be focused on these. The
results of this study have led to the conclusion that the present unstable to
critical conditions of some portions of the Diwalwal study area is primarily
due to two factors: generally poor ground conditions; and unrestrained and
unsystematic human intervention, mainly logging and mining. While naturally
unstable areas are relatively common in some areas, human activities have
gravely exacerbated the instability and hastened the process of mass movements.
Terrain
analysis and classification was carried out over the entire proposed Diwalwal
Mineral Reservation area to evaluate zones suitable for the resettlement of
small-scale miners community occupying high risk zones in Diwalwal. The terrain
classification map produced shows four (4) major Terrain Mapping Units (TMU’s)
within the said Mineral Reservation. These are the plateau-like terrain; the
high hill and its slopes; the mountainous terrain and karst terrain.
Monitoring of Gold Recovery
from the Government Share
of Ores Diwalwal Direct-State Utilization Project
Voltaire
Villadolid, Vernadette de Guzman, Rey Perucho, Edwin Santelices
METD, MGB
CO
In the Diwalwal Direct-State Utilization Project, the 15% share of the
government, in the form of gold ore from the small-scale miners, is processed
in a mineral processing plant that was contracted by the government through
Natural Resources Development Corporation (NRDC) and Mines and Geosciences
Bureau (MGB). Previously, the
government ore was processed in Nabunturan, Compostela Valley under Ruthsil
Minerals Inc. As of June 2003, the
operation was transferred to JB Management Mining Corporation in Monkayo, Davao
del Norte.
This report
includes the general flow of materials from the ore to gold bullion with
emphasis on critical points where monitoring activities are undertaken to
ensure optimum recoveries with minimal metal losses.
The Provincial Mineral resources Development Plan An Integrated Approach
in the Development and Revitalization of the Mineral
Industry
Richelle C.
Awid, Genevive P. Chua, Romeo M. Dalodado,
F.S. Monteros with
Hon. Robert
Lyndon S. Barbers
Provencial
governor – SDN
Chairman –
RDC Caraga
MGB R-XIII
The pursuit of
integration and balance had emerged as a key principle affecting virtually all
aspects of the human enterprise. In the field of development planning the
panoply of interrelated thrusts and approaches to change redefines concepts of
growth and progress. Holistic and
sustainable development became common usage providing broad theoretical
frameworks in affecting a profounder vision of improved quality of life.
Translating these theories into concrete course of actions presents one of the
challenges facing society today.
Surigao del
Norte being naturally endowed with a
wealth of mineral heritage, the integration of mining in the overall
development scheme of the province presents a major paradigm shift in
development planning. Diverse perceptions on mining and conflicts in land-use
are some of the existing concerns and anticipated problems that must be
resolved in order for the industry to truly earn its claim as a major
benefactor of society.
The call to
revitalize the mining industry should not be treated in isolation as purely the
task of the DENR-MGB alone. Strategy to
raise the level of awareness and understanding on mining development
perspectives, synchronize development thrusts and harmonize land-use demands
hass to be rationally formulated.
Thus, the
Provincial Mineral Resource Development Plan (PMRDP) endeavors a
development blueprint that shall
address the social, political,
economic, environmental and cultural perspectives, among others, of the
different sectors of society.
Spearheading the formulation of the PMRDP is the multi-sectoral
Provincial Mineral Resources Management Committee (PMRMC) created by the
Provincial Governor to serve as an avenue for development convergence.
With the
completion of the comprehensive mineral
resources development plan, the attainment of a revitalized mineral industry is
envisioned to create a brighter prospect for the future of the province that
will eventually be used as a model for a unified regional, if not national
effort.
Ceramic/Pottery Industry of Sta. Maria Isabela
A.m.
Chumacog, F.V. Piligan, N. nb. Tabanao, D.B. Corsino
MGB R-II
This study
assessed the social and economic contribution of the ceramic/pottery industry
in Sta.Maria, Isabela, explored the clay deposit and identified problems
encountered by the respondents.
The
calculated clay reserve in the area is approximately 500,000 cubic meters with
an average thickness of 2 meters and covering an area of about 25
hectares. It was classified as an
alluvial/flood plain clay with characteristics not suitable for making
whitewares. They are generally used in
making earthenware pots, jars, stoves, bricks and tiles.
The social and economic contribution of the ceramic/pottery industry had
only been minimal despite its wide market potential and abundant source of clay
materials. Approximately 88% of the
ceramic/pottery makers in Sta.Maria has a monthly income of less than Ph1500
and 89% of them only had elementary education.
The
problems plaguing the industry are: 1) lack of capital for production and
marketing, (2) lack of facilities/equipment to boost productivity and improve
product quality, (3) unfavorable competition that pulls prices down,(4) lack of
expertise and skill to produce quality products that are more saleable and (5)
lack of ready or regular market where the products can be sold.
To address
the problems of the industry and alleviate the economic status of the residents
depending on it, it is recommended that a sustainable, effective and competent
cooperative be established through proper training seminar, assistance and
coordination among ceramic/pottery makers and with pertinent government
agencies particularly the Cooperative Development Authority (CDA) and
Department of Trade and Industry (DTI).
The Mines
and Geosciences Bureau-Region 2 (MGB-R02)
in coordination with the Department of Science and Technology-Region 02
(DOST-R02) and Industrial Technology Development Institute (ITD) of the
DOST-Manila can provide technical assistance and help the pottery makers
enhance their skills and upgrade their facilities/equipment.
Mining in Partnership:
The Acupan Experience
Felizardo
A. Gacad, Jr.
MGB CAR
Benguet Corporation (BC) pioneered
modern mining in the Philippines in 1903.
At its peak, BC employed 8,000 miners in three of its mines in Itogon
namely: Acupan, Antamok and Kelly, and was the province’s biggest employer.
However,
the July 16, 1990 killer earthquake, coupled with the rapid spiraling down of
the pride of gold, precipitated the suspension of the underground mining
operations of BC. In turn most of the
miners were laid off. Due to the
limited employment opportunities, the miners resorted to small-scale mining
around BC’s mining claims.
In an
effort to provide a legal means of livelihood to the community, generate taxes
for the LGU and generate income for the stakeholders, the Acupan Contract
Mining Project (ACMP) was conceived.
This paper
will attempt to discuss the experience of the BC, the LGU and the MGB-CAR in
relation to re-opening the Acupan mine in partnership with the small-scale
mining operators.
Joint Geo-Scientific Cruise Between the MGB and NAMRIA
as part of the
Mapping of Philippine Exclusive Economic Zone (EEZ)
Seafloor
Marcelo M.
Alilio and Leopher G. Dagdag
MGSD, MGB –
CO
A joint geo-scientific cruise between the Mine and Geosciences Bureau
(MGB) and National Mapping and Resource Information Authority (NAMRIA) was
conducted in the offshore western part of the Philippine Archipelago in May
2002. This is in line with the inter-agency mapping of the Philippine Exclusive
Economic Zone (EEZ) seafloor for establishing technical basis as well as
supporting geo-scientific evidences for the Philippine Government’s claim for
an extended continental shelf.
The two
research vessels of NAMRIA, namely BRP Hydrographer Presbitero and BRP
Hydrographer Ventura, were utilized as the survey platform. Gravity, magnetics
and sea-bottom topographic surveys were carried out simultaneously during the
cruise.
Based on preliminary interpretation of the data gathered during the
cruise, the prominent features in the coverage area are the north-south
trending depression, the Manila Trench, with a maximum depth of 5,500 meters
and curved eastward at the southern portion of the area towards Mindoro which
corresponds to the elongated north-south trending gravitational anomaly in the
area; the Bajo de Masinloc seamounts, which are observed in the western portion
of the area, has a circular pattern anomaly with a gravitational high at its
center. It is a series of westerly trending dome-like structures with a height
from the seabed of about 3,000 meters; the Mindoro-Palawan micro-continental
platform, which is a bathymetric high and a magnetically quiet zone in the
southeastern portion of the area and is in the southern end of the Manila
Trench.
Mass Movements at the Upper
Reaches of Pamacngan Creek:
It’s
Implication to the Heavy Siltation Occurrences
along Subang Daku River System, Sogod, Southern Leyte
Cesar L.
Balce, Ricardo H. Obtinalla, Jr. and James S. Leones
MGB R-VIII
The
numerous recurring problems on heavy siltation being experienced at the
midstream and downstream segments of Subang Daku River of Sogod, Southern Leyte
can be traced to be inherent to the general lithologic as well as structural
condition at the upstream.
The bedrocks along Cabadbaran River, which is
a main northeastern trending tributary of Subang Daku River, are highly erodable. The rocks are usually intensely fractured,
altered and loose exposures of andesite flows, ultramafic diapirs and
pyroclastic deposits. The active Philippine Fault Line, which passes in
upstream portion of Cabadbaran River is the main cause of the bedrock fractured
condition.
The headwater of Pamacngan
Creek, which is the northeasternmost tributary of Cabadbaran River, is
highly unstable. Numerous scarps of previous landsliding occurrences are noted
in the area. At least two(2) massive dormant landslide manifestations have been
observed which are dangerously threatening to move downslope if induced by
heavy rains/typhoons and even the occurrences of strong earthquakes. It is estimated that its movement with the
aid of flowing surface water will trigger a domino effect that will affect the
voluminous debris deposits along the sides of the creek. It is calculated that
a possible amount volume of about 1.5 to 1.8 million cubic meters of rock and
soil debris materials may flow downstream of Subang Daku River.
This volume
of sediments may double the present deposit of sediments in the river and may
cause flooding of near-riverbank communities/settlements
Environmental
Responsibility and Sustainable Development
Utilizing
Social and Community Development Perspective
Marcelino
G. Gamutan
CDO,
MGB-XII
Given its existing tract records, MGB XII has yet to go pro-active in
terms of responding to the wholistic aspirations of the stakeholders in the
mining areas. It must be deeply
understood that the stakeholders are not so much concerned, per se, with the
minerals found in their communities.
The IP’s in the area (the B’laans and the T’bolis) hardly verbalize it,
but during their long community reflection sessions, which the MGB XII
conducted, both formal and informal, the natives brought out concerns beyond
the minerals. One of this is the future
of their children.
Here MGB
XII stopped short of giving this its total attention. A great number of MGB XII’s activities were spent with the clients’
compliance of its bureaucratic requirements and obligations. It is, therefore, in this area that good
governance with an ample dose of partnership and participation needs
re-thinking and re-designing. The
proposed intervention needs actual and delicate balancing in the field
level.
Concepts
and activities in the proposal are here presented wherein the seemingly
never-ending concerns of both environmental responsibility and sustainable
development will be met head-on with challenging engagements. Innovative educational tools and logistics
will be utilized for its purpose.
Consciousness-raising is paramount objective.
Good
governance and transparency are achievable objectives only when the IP
communities arrived at a common vision.
For the people to want mining activities in their area to succeed, they
must first WANT and NEED mining. Herein
lies the dream, and better yet, implement this in concrete realities. This and among others, the program intends
to achieve.
As everyone
in the Bureau understands the tripartite mining development model, it is
suggested that both benefits and responsibilities must be shared and shouldered
by ALL parties concerned. For the MGB
XII’s participation comes in its willingness to creatively re-study its
bureaucratic policies. As for the
communities, the people must be open enough to undergo changes in their tribal
structures and culture. And finally,
for the company consciously doing business in the area must be
culture-sensitive. In totality, this
will be industrial peace in focus.
Mineralogical Descriptions of the Bentonite
in Balamban, Cebu Province, Philippines
Dennis
Gerald A. Aleta*, Katsutoshi Tomita* and Motoharu Kawano**
*Department
of Earth and Environmental Sciences,
Faculty of
Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima City, 890-0065 Japan
**
Department of Environmental Sciences and Technology, Faculty of Agriculture,
Kagoshima
University, 1-21-24 Korimoto, Kagoshima City, 890-0065 Japan
(Received
June 5, 2000. Accepted November 29,
2000)
The clay
mineralogy of bentonite in Balamban, Cebu Province, Philippines was
studied. Specimens were randomly
collected from lenticular seams of bentonite concordantly intercalated with
sequences of calcareous and tuffaceous shale and sandstone of the Middle
Miocene Toledo Formation. Multiple
analytical techniques of the <2μm size fraction reveal that smectite is
the dominant clay constitution of the bentonite. Minor association of mixed-layer kaolinite/smectite, kaolin and
mica is indicative. Diagenetic facies
of calcium-rich bentonite and cristobalite-rich bentonite are diagnostic
features. Non-phyllosilicate components
are mainly quartz, feldspar, cristobalite, calcite, and zeolite. Volcanic glass shards, considered as the
precursor material, occur sporadically in the clay-dominated matrix. Calcareous microfossils or nanofossils also
exist as subordinate impurities.
Rehydration
capacity of the calcium-rich bentonite was observed to be generally greater than
the cristobalite-rich bentonite.
Bentonite
formation is ascribed to be generated by halmyrolysis of the volcanic glass
fragments contained in the vitric tuff exhalative unit of the Toledo
Formation. The devitrification and
transformation of the glass into nearly pure smectitic clay suite apparently
ensued in a marine environment.
Diagenetic formation of the calcium-rich facies appears syngenetic with
the accumulation of the volcanic ash in saline waters while the
cristobalite-rich facies appears authigenic, constituting the silica-rich
layers.
Dipolog City Airport:
An Assessment of its Susceptibity to Geologic Hazards
Roman
C. Santos
MGB
R-IX
The
Geologic mapping conducted for the Dipolog Quadrangle resulted in the
determination, not only of lithologic units and structures, but also of other
significant information such as the susceptibility of Dipolog City and its
environs to a variety of site-specific geologic hazards. Particular attention
was given to the Dipolog City Airport owing to the nature of geohazards
identified threat.
Geomorphologic
analysis shows that the airport was constructed atop a southwest migrating
spit. The Underlying materials comprise waterlogged, well sorted,
unconsolidated, medium- to very coarse-grained to gravelly-sands. As such, it
is suceptible to hazards induced by seismic activity.
However,
immediate threats to the airport are those posed by geologic hazards resulting
from coastal processes. It has been determined that the coast has retreated
Approximately
26 meters during tha past 27 years. Considering that the existing buffers zone is less than 50 meters from the edge of
the runway to the shoreline, continued erosion could jeopardize the operation
of the airport.
Sediment
depletion can be traced to modifications
made on the coastline, i.e. the construction of a seawall and of a jetty. In
the case of the latter, the jetty was constructed fronting the southern tip of the spit in order to
arrest longshore sediment drift. Needles to say, said structure only exacerbated
the problem.
It
is recommended that prior to any further coastal developments within the area,
comprehensive geological survey should
first be conducted order to ascertain the viability of the project.
Land Use Capability
Analysis of the Talomo-Lipadas Watershed Area, Davao City
N.B.
Angeles, V.F. Valerio, R.L.E., D.K.B. Velasco, R.T. Villamor
MGB-R-XI
The
Talomo-Lipadas Watershed is the main source of potable water of Davao
City. The watershed encompasses a total
area of approximately 38,300 hectares and includes portions of Toril, Calinan,
Tugbok and Talomo Districts.
To maximize
the sustainable use of this resource, it is necessary that physical development
within this watershed area be properly planned with the aid of relevant
scientific tolls. Land use
analysis capability is the essential
first step in determining the types of development that may be accommodated
within the Talomo-Lipadas Watershed Area (TLWA).
Analysis
was done mainly through applied geomorphology, which involved acquisition of
secondary data, interpretation of aerial photographs, field investigation and
laboratory analyses of soil samples. The TLWA was subdivided into seventeen
distinct terrain mapping units corresponding to five fluvial, ten volcanic and
two denudational landforms based on geomorphology, slope class, lithology and
soil type. Physical parameters such as
flood, erosion, landslide, and liquefaction susceptibility, groundwater
potential, groundwater recharge, soil leaching potential and groundwater
vulnerability were then derived for each terrain mapping unit.
The
capacity of each unit to accommodate general land uses(i.e. residential,
commercial, industrial, institutional, agricultural, tourism, conservation and
forest zones) were established by determining distinct numerical values for
each physical parameters, with the addition of current land use patterns and
proximity to an existing road network.
Acceptable values were then established for each land use and
correspondingly mapped per unit.
Based on
the analysis, there is a need to modify the original development plan of the
city government specifically within the Talomo section of Calinan District,
because of its incapability to support medium to heavy development owing mainly
to its high groundwater vulnerability.
To determine the best levels of development and non-development within
the watershed area and ensure sustainability, urban and environmental planners
may also use the results of this study.
Geo-Environmental
Survey|: Coastal and Geohazard
Assessments
from
Tobias Fornier, Antique to San Jose, Antique
Mae Y.
Magarzo, Pamela Gerrez V. Tañeza, Ma. Lucille V. Fuentes
MGB-R-VI
The
technical team from the Geosciences Division of the Mines and Geosciences Bureau
– Region VI conducted a geo-environmental survey that includes coastal and
geohazard assessments, well inventory and monitoring. The study area covers the coastal portion of Tobias Fornier,
Hamtic, and San Jose, Antique. The 515
hectares project area includes the entire coastal towns and its mountainous
road networks.
The
objectives of the study are to identify the geologic hazards along the coastal
road, to assess/investigate the degree of coastal erosion/degradation and storm
surge, to investigate and assess the extent of possible seawater
intrusion/dilution of groundwater and to recommend mitigating measures in order
to minimize the negative effects of the identified geohazards.
The
different geologic hazards observed in the study area include coastal erosion,
storm surge, river erosion, soil slide and flooding. The overall result of the deepwells that were randomly sampled
from the three municipalities has a percentage of 39.13% in salinity reading.
Groundwater Exploration and
Development in Santa, Ilocas Sur
Rogelio M.
Faminialagao, Socrates G. Gaerlan, Teofilo O. Mazon, Jr.
MGB-I
Last January 14 to January 19, 2002, the
groundwater exploration survey was conducted by the Mines and Geosciences Bureau
personnel in the Municipality of Santa, Province of Ilocos Sur. This is in connection with Memorandum of
Agreement (MOA) made and entered into last November 15, the 2001 between the
Province of Ilocos Sur represented by the Hon. Deogracias Victor B. Savellano
and the Mines and Geosciences Bureau represented by Regional Director Samuel T.
Paragas.
The main objective of the survey is to
explore and eventually develop the groundwater resources within the identified
potential areas in order to sustain a continuous supply of fresh potable water
for the NEW KIDS FARM.
Three teams of technical personnel were
dispatched simultaneously to conduct the hydro- geological, piezometric and
water quality and geophysical exploration survey to identify the different rock
formations within the vicinity, ascertain the presence or absence of
water-bearing beds or strata, delimit the unproductive areas, static water
table and water quality sampling and ascertain the sub-surface lithological and
stratigraphical sequences of the underlying formation by vertical electrical
sounding (VES).
Based from the study, three (3) sites were
identified as possible site for groundwater development, however, the
provincial government of Ilocos Sur prioritized drilling inside the NEW KIDS
FARM, its flagship project that propagate different imported animals.
Drilling Team of Mines and Geosciences Bureau
was mobilized to the site last July 16, 2003, and drilling of borehole commence
last July 26, 2003, using the brand new MRA-260 rotary drill with 6” diameter
mill tooth tricon bit mounted to it.
After reaching the target depth of 78 meters, well development and
construction followed.
To determine
the hydraulic properties of the well and the aquifer tapped, constant discharge
test was carried out for 12 hours and information gathered confirm good
confined aquifer in the area having specific capacity of 35 gal/ft draw down.
Engineering
Geological Study on the
Proposed Salvacion, Macawayan 1 and
Macawayan 2 Farm-to-Market Roads,
Bgy. Manamrag, San Andres, Catanduanes
Arlene
E. Dayao
MGB
R-V
An
engineering geological assessment of the proposed Salvacion, Macawayan 1 and
Macawayan 2 Farm-to-Market Roads was undertaken per request of the Chief
Executive of San Andres, Catanduanes. The
infrastructure project would involve the construction of a 100.40 m. multi-line
spillway (RCPC) and a 6 m. wide gravel road having an aggregate length of
3.36707 kilometers in Bgy. Manamrag.
The study involved sub-surface soil mapping using an Eijkelkamp hand
auger. Drilling was done at an interval
of 100 m. along the 3 road segments.
Each soil layer in the profile was sampled, logged and submitted for
complete grading, moisture content, Atterberg limits determination, compaction
and CBR. Construction materials from
prospective quarry sites for fill materials, like the Manamrag and Macawayan
Rivers, were likewise sampled for compaction analysis and CBR. The type, origin
and the nature of occurrence of sub-surface soils as well as the geologic hazards
that could possibly occur at the site were assessed. Underlying rocks
were mapped from drill holes as well as from exposures along the proposed
farm to market roads.
In
addition, groundwater levels were measured from drill holes. Permeability and/or hydraulic conductivity
of certain soil layers was measured using the slug test method. Surface water condition was also observed,
particularly water levels along the swamp on the terminal end of the proposed
Salvacion Farm-to-Market Road.
Interviews were made along local residents regarding swamp water levels
during regular high and low tide periods as well as maximum flood levels during
typhoons.
Study
reveals five different soils classified according to nature and origin. These are the footslope deposits, the beach
sands, the coastal gravels, the alluvial plain deposits and the riverbed and
floodplain deposits. Results of
laboratory tests were used to further classify these soils according to the
Unified Soil Classification System that showed that the footslope deposits
consists of gravelly sandy clays (CL), inorganic silts (ML), clayey sands (SC)
and silty sands (SM). The beach
deposits largely consists of poorly graded gravelly sand (SP) and well-graded
gravelly sands (SW). These sub-grade materials have excellent drainage
characteristics, good bearing values and CBR values of 10-40%. Thus, “capping” maybe unnecessary. However, since the uppermost 20 cm. of these
deposits are very loose, this topmost 20 cm. portion need to be scraped off or
mixed with silts and gravels and be properly compacted before the final fill
and gravel surfacing is made.
The
riverbed and floodplain deposits along Macawayan River was tested to have CBR
values of 30%. This would mean that
sub-grade materials from traverse station 19 through 23 and traverse stations
26 and 27 are very good and “capping” would be unnecessary for these portions
of the Macawayan 2 FMR.
The rest of
the soils were likewise characterized in terms of drainage characteristics,
value for foundation, unit dry weight and California Bearing Ratios and
appropriate recommendations were provided in the report submitted to the local
government unit.
Progress Report on
the Hydrogeological Assesment
of Mogpog Municipality, Province of
Marinduque
Evelyn M.
Diezmo, Socorro P. Hernandez, Romali S. Umali
MGB R-IV