Mining Pollution: the Case of the Baguio Mining District, the Philippines NICOMEDES D. BRIONES Environment and Policy Institute East-West Center Honolulu, Hawaii 96848, USA

ABSTRACT / Environmental problems caused by improper mine tailings disposal in the Baguio district include pollution of the Lower Agno River system and its watershed and silta- tion of irrigation canals in the Pangasinan plains. Direct eco-

nomic losses are from reduced agricultural production due to siltation of irrigation works and farmlands. To check the ad- verse ecological effects of improper mine tailings disposal, government regulations have been imposed on mining firms. Several disposal schemes have been proposed, including the use of the reservoir of a multipurpose project to be sited in the watershed where the mines are located. Because of siltation problems, however, trapping the tailings in the reser- voir will diminish the economic benefits that can be derived from the project.

The Philippines is considered one of the world's highly mineralized countries in terms of minerals per unit area of land. For example, the country has the world's largest deposits of chromite and one of the richest nickel reserves. The total mineral reserves of the Philippines is estimated at 36.2 billion metric tons (MT), 66% of which is accounted for by nonmetallic ore reserves and the remaining 34% by metallic re- serves (NEEP 1983). At present, most of the mining activities are concentrated in Luzon's Baguio Mining District, where metallic reserves such as. gold, silver, and copper are the largest in the nation.

The mining industry has always been a major con- tributor to national economic growth and develop- ment. Its significance lies in its contribution to employ- ment, capital accumulation, and foreign exchange earnings. For a developing Philippine economy, the mining sector is an indispensable source of funds to improve the country's balance of payments. Although it accounted for less than 2% of the net domestic product, the annual contribution of mining as a source of foreign exchange earnings was about 18% of the total receipts for the period of 1971-1984 (NEDA 1985). The majority of the Philippine mining share is derived from the exports of copper concentrates, gold, iron ore, and chrome ore.

While the industry has brought economic benefits, it has also taken its toll on the environment. In 1977, there were 39 mining firms dispersed along the major river basins of the Philippines. Of these, 24 mines were active mineral-producing firms generating 220,000 MT of raw ore daily. About 140,000 MT of mine tailings were being discharged daily into eight rivers,

KEY WORDS: Mine pollution; Water quality; Watershed management; Siltation; Mine tailings

consequently damaging about 190,000 ha of farmlands (Villavicencio 1977). As the tailings are transported down the streams and rivers, the beds become shal- lower, leading to overflowing with consequent flooding of the outlying areas. The tailings accumulate at lower elevations and clog irrigation canals, ricefields, and reservoirs.

It has been recognized that pollution and siltation of main river systems within the immediate vicinity of mine sites of Baguio Mining District is due to im- proper disposal of mine tailings. This article discusses the problems and economic implications of mining pollution in the highly mineralized area in Baguio, the Philippines. Alternative mine waste disposal methods, including the use of the proposed reservoir of the San Roque Multipurpose Project as a dumping site, are also presented.

The B a g u i o M in ing Dis t r ic t

In an area of a few kilometers southeast of Baguio City in Luzon is a mining site which is drained by the Twin River, a tributary of the big Agno River. It lies in a mountainous region characterized by sharp edges and steep slopes. This area is collectively designated as the Baguio Mining District, which is considered as the most important and productive mining area in the Philippines (Figures 1-3). Several active mines and mine prospects are clustered along a north-south trending belt with an approximate area of 260 km 2.

The most common problems of the mines in the district is how to dispose of the mine tailings properly. After ore milling and concentration, the mines dis- charge the railings into neighboring creeks; thus, downstream of the mines all streams are polluted to varying degrees. The total daily tonnage of discharged

Environmental Management Vol. 11, No. 3, pp. 335-344 �9 1987 Springer-Verlag New York Inc.

336 N.D. Briones

Baguio Mineral District

0 50 1fib 150 200 250 Krrl

I N

O

- - 1 7 ~

C~

Z N 15~

Figure 1. Location map of the Baguio Mining District, Luzon, the Philip* pines.

Figure 2. Aerial view of a typical mining site, Baguio Mining District, The Philippines.

Figure 3. Aerial view of mining roads, Baguio Mining Dis- trict, The Philippines.

mine tailings is approximately 50,000 MT and is ex- pected to increase in the coming years. This quantity, which flows into the Agno River and other nearby creeks, has caused a considerable amount of damage to the agricultural system and aquatic resources. Mine pollution in the area affects four river systems and hundreds of thousands of hectares of farms in the lowland areas of the provinces of Pangasinan, La Union, and Ilocos Sur (Table 1).

Philex Mines, the largest company operating in the

district, started operation in 1958 and by 1983 had 3000 employees. The mine, which uses the block- caving mining method, has a remaining lifespan of 40 years. The railings produced by this mine represent 90% of the total railings volume produced within the Lower Agno River watershed and nearly 80% of the overall ore or tailing volume mined in the Baguio Dis- trict. At present, Philex Mines' tailings are impounded in two company-constructed tailing dams that are being gradually built up on a right bank tributary of

Mining Pollution in the Philippines 337

Table 1. River systems affected by mines, Baguio Mining District.

Quantity of tailings River system Province Mining company produced daily (MT) affected affected

Philex Mines 27,000 Agno Pangasinan Western Minolco a 14,000 Amburayan Ilocos Sur Baguio Gold 7,400 Amburayan La Union Black Mountain, Inc. b 2,470 Bued La Union Benguet Consolidated, Inc. 1,974 Agno Pangasinan Lepanto Consolidated 835 Abra Ilocos Sur Itogon-Suyoc Mines 120 Agno Pangasinan Atok- Big Wedge c 100 Agno Pangasinan Benguet Exploration 87 Bued La Union

Not operating since November 1977. b Suspended operations in 1983. c Not operating since 1976.

the Agno River. These two dams will reach capacity by 1987. The construction of a third dam was started in 1978 but it was stopped in 1979 because of the govern- ment's plan to construct a multipurpose reservoir downstream to impound mill railings from the mines in the watershed.

Mine Tailings Disposal

The three tailings disposal measures generally adopted by the country's mining companies are (a) di- rect disposal to the sea, lakes, or rivers, (b) backfill method, and (c) tailings-pond method.

Direct Disposal to the Sea, Rivers, and Lakes

The tailings are directly disposed into the sea, rivers, or lakes by means of pipelines and launders (box conduits conveying particulate materials sus- pended in water in ore dressing). Suspensions of solids in water bodies can affect and destroy aquatic life and fisheries. I f water is turbid with suspended solids, pho- tosynthesis by phytoplanktons can take place only near the surface, so that primary production will be drasti- cally reduced (Holme 1978). Ultimately, fish and other aquatic organisms that directly or indirectly depend on planktons are also affected. However, disposal to the sea seems to be the accepted solution in the Philip- pines. The biggest mine in the country (Atlas Consoli- dated Mining Company) disposes most of its tailings to the sea. The firm has designed, constructed, and now successfully operates a 47-km system of pipelines and open launders or flumes for transporting tailings by gravity to the sea (Gaddi 1981).

Backfill Method

The tailings are used as fillings for underground openings that are mined out or no longer in use. By

this practice, which is successfully being adopted by Benguet Mining Corporation, 60% of the generated tailings are recovered and returned underground. Kennecott Copper Corporation in the USA also uses this method (Mantell 1975). However, this system is limited to underground sloping mines and not appli- cable in other underground mining methods such as block-caving, where ore extraction is enormous (Bug- nosen 1981).

Containment in Tailing Ponds

This is the most widely used tailings disposal system in the Baguio district. The tailings are directed into a pond constructed with the use of dams or dikes (Figures 4-7). Tailings dams are generally built by using the coarse sand component of the tailings to form the embankment. The railings particles settle while the decanted effluent is allowed to flow into the drainage system or sometimes recycled. This method has several disadvantages. Failure to properly main- tain the dams can result in tailings escaping into the natural drainage system and consequently into the irri- gation canals and farmlands and other infrastructures. Strong storm events can cause washouts of the tailings dams.

The tailings coming from the mine processing plants in the Baguio Mining District are conveyed by means of gravity launders to railings ponds formed by damming nearby creeks. The tailings dams are raised gradually, with the precise pattern following the in- crease of sediment level in the pond. Diversion works and tunnels divert the natural river flow and floods from the creeks upstream of the ponds to avoid over- topping of the dams and softening of the sediments. However, these dams suffer occasional collapses due to strong rains that prevail in the area, especially during the rainy season. At present, a large volume of

338 N.D. Briones

Figure 4. A mine tailings pond that is almost filled up to capacity.

Figure 5, Aerial view of a tailings pond, Baguio Mining Dis- trict, The Philippines.

Figure 6. Aerial view (downstream side) of a tailings dam. A Figure 7. Upstream aerial view of the railings dam and reser- bulldozer is piling up the tailings to increase the dam's height, voir.

mine tailings is being released and reaches the Agno River, thus heavily polluting its waters.

The construction of a railings dam is costly for the mining companies and is therefore carried out with extremely limited investment. The stability of the railings dana therefore is very uncertain, and the ponds represent a serious threat to public projects and private properties downstream.

Ecological Effects of Improper Mine Tailings Disposal

All mining activities create an imbalance in the envi- ronment by altering landforms and physiography, disrupting the hydrologic cycle, and discharging wastes into the rivers and polluting them with toxic wastes. Mineral development activities such as the ex- cavations in open-pit mining, block-caving, ground preparation, including construction of roads and

building facilities, inevitably disturb the environment. Milling operations produce tailings, which, if not properly disposed, could easily find their way into nat- ural river systems, resulting in the sedimentation of riverbeds and agricultural lands. When rocks and wastes are dumped to lower levels, trees are usually cut down or buried. The heavy-metal components of the wastes are subject to leaching and can adversely influ- ence water quality. Acid water is also an undesirable discharge from the mines.

Mill tailings provide a hostile environment to plants because they are deficient in important soil nutrients, have excessive salts and heavy phytotoxicants, and lack microbial populations; moreover, physical damage is caused by unconsolidated sands that, when wind blown, destroy young plants and seedlings. Mill tailings are also toxic and destructive to much aquatic life, because of the effects of heavy metals, reagents, and suspended solids.

Mining Pollution in the Philippines 339

Table 2. irrigation systems affected by mine tailings.

Estimated Volume of Total volume of mine tailings

service Irrigated mine tailings per meter Irrigation area area in irrigation of canal system (ha) (ha) canals (m s) (m3/m)

Agno 18,509 12,095 509,093 3.20 a Lower Agno 8,001 7,515 42,846 3.75 b Bued 2,766 2,766 33,606 c Amburayan 3,705 3,553 57,463 0.33 d

a Based on samples taken from 3 main canals and 1:3 lateral canals.

b Based on samples taken from 6 lateral canals.

c Not available.

d Based on samples taken from 2 main canals and 2 lateral canals.

Agricultural Production Loss

Downstream of the mine sites is a productive and heavily populated areas collectively known as the Pan- gasinan Plains, occupying both banks of the Agno River. Rice is the primary crop in the area with corn, tobacco, mungbean, and peanut as secondary crops. Yields are generally low due mainly to undependable supply and low quality of irrigation water (NIA 1983). In this area, the National Irrigation Administration (NIA) operates several irrigation systems covering a service area of 33,000 ha. The canal network of the irrigation systems is, at present, in rather poor condi- tion because of operations and maintenance problems due to heavy siltation caused by mine railings, as shown in Table 2 (NIA 1983).

The Agno River Irrigation System (the largest irri- gation system affected by mine pollution) started operation in 1958 and has a total service area of 18,509 ha, 35% of which is unirrigated due to siltation from mine tailings. It is a diversion-gravity type that gets its water from the Agno River through a diversion weir downstream of the mines at San Roque gorge. The sediment-laden water of the river had brought maintenance problems to about 52% of the 222.27 km of main canal and laterals of this system. As early as 1963 sedimentation of the canals was already a big problem. On the basis of data collected at a cross sec- tion of the main canal, 2 km from the diversion head- gate, an annual average of 450,000 MT of sediment were being deposited along the canals and farm areas served by this irrigation system (Saddam and Prospero 1963). Sand from the river had been traced to the far- thest laterals. The extent of damage to the Agno River Irrigation System in 1977 was estimated at a loss of 25% of its designed capacity because of silting at the intake structure (Peters and Kitching 1978).

By 1978, the annual damage attributable to mine tailings had been estimated to be US $5.75 million, US $8.49 million, and US $8960 for Amburayan River Ir-

Table 3. Losses due to mine tailings siltation of irrigation systems (1978 prices).

Annual loss (million US$)

Cause Amburayan Agno Bued

Loss due to silting of canals (rehabilitation) (1970- 1977) 0.20

Loss due to uncollected irrigation fees (1970- 1977) 0.06

Loss due to crop yield reduction (1970-1977) 4.44

Loss due to the inability to irrigate parts of the service area (1970-1977)

Total

1.73 0.009 a

0.36 __b

6.36 c b

1.05 0.04 c b

5.75 8.49 0.009

a For the period 1973-1977.

b No est imamsmade.

~For the period 1976-1977.

rigation System, Agno River Irrigation System, and Bued River Irrigation System, respectively (NIA 1978) (Table 3). The losses had been attributed to siltation of canals, crop yield reduction, inability to irrigate the service area, and uncollected irrigation fees. The total farm area affected was 122,757 ha located in the prov- inces of Pangasinan, La Union, and Ilocos Sur.

In fresh unweathered form, the mill tailings contain very little assimilable plant nutrients and in the rice- fields where such sediments are deposited and mixed with the existing soil by plowing and harrowing, the soil fertility had diminished every year. The conse- quences of uncontrolled irrigation water siltation by mine wastes have been determined by several studies (Mercado 1974, Sulliven 1967). Mine wastes have high acidity and dissolved solids that pollute irrigation water, which results in water which is slightly toxic to plant growth. The lower pH changes the stability and mobility of numerous elements and salts in the soil. In addition, continuous siltation has raised the elevation of the farms so that they require leveling to insure proper distribution of irrigation water.

Based on the population whose livelihood depends directly on agriculture in the area, calculations indicate that the number of people adversely affected in 1980 by these mine tailings was about 146,000.

Hydrobiological Effects

In addition to the effects on agricultural produc- tivity, mine tailings also adversely affect the microbio- logical regime of the Lower Agno River. In a fishery survey conducted in a proposed damsite (BFAR 1983), identified fish species such as gobies, eels, mudfish,

340 N.D. Briones

black bass, and tilapia were found to be very rare. Of the nine species of phytoplankton identified, only three species were considered abundant while the rest are rare. All of the four kinds of zooplanktons identi- fied were rare. Virtually no floating, emergent, or submerged aquatic vegetation has been found.

The absence of abundant fish and other forms of aquatic life is attributed to the high water turbidity caused by great amounts of fine suspended sediments from the mine railings. The turbidity reduces light penetration and limits the photosynthetic activities of the phytoplanktons. The resulting decrease of micro- bial population adversely affects the higher forms of aquatic life, especially fish that directly depend on planktons for sustenance.

Government Policies on Mine Tailings Disposal While government concern covers all mining oper-

ations in the Philippines, it has been more or less fo- cused on the degradation caused by the mining opera- tions in the Bagnio Mining District. Because of the ex- tent of pollution and siltation caused by the mining industries, Presidential Decree (PD) no. 463, known as the Mineral Resources Development Decree of 1974, was issued defining the government policies on mine tailings disposal, mineral conservation, rehabilitation of mined-out areas, safety, and socioeconomic devel- opment in mining areas. This decree was further amended by PD nos. 1385 and 1677. Among the sa- lient features of the decree are (a) the submission by mining firms of their long-term plans for the protec- tion and enhancement of the environment, (b) the im- plementation of a work program designed to rehabili- tate, regenerate or revegetate mined-out areas, and (c) the provision of appropriate pollution control mea- sures to prevent further damage to the environment. In order that the requirements of the decree can be implemented properly, the mining firms are required to put up an "environment protection and enhance- ment unit" and to allocate at least 1/2% of the total yearly operating budget to finance the environmental protection activities.

Presidential Decree no. 1151 (as amended by PD 1586) was issued in 1977 requiring the submission of Environmental Impact Statements (EIS) which aim primarily to identify, predict, interpret, and communi- cate information regarding the changes in environ- mental quality associated with a proposed project and to examine the range of alternatives for the objective of the proposal and its impact on the environment. Under this system, a company proposing a mining project that has significant effects on the environment must prepare an EIS that would identify existing envi-

ronmental conditions in the proposed project site and furthermore would contain mitigating measures to be undertaken in the course of operations to protect the environment. This function is under the supervision of the National Environmental Protection Council (NEPC), a public agency created primarily to assure the people of a safe, decent, healthful, and productive environment.

Several government agencies have been mobilized to safeguard the environment from mining pollution and specifically to design programs to solve the railings problems in the Bagnio district. These include the Na- tional Pollution Control Commission, the Ministry of Public Works and Highways, National Power Corpora- tion, National Irrigation Administration, and the Bureau of Mines and Geosciences. Representatives from the mining companies operating in the district work together with these agencies.

Proposals to Dispose of Mine Tailings To find a permanent solution to mine tailings dis-

posal in the Bagnio Mining District, the government has sought the assistance of several international orga- nizations, such as the United Nations Environmental Programme and the Japan International Cooperation Agency, in designing mine disposal schemes.

Japanese International Cooperation Agency (JICA) Proposal

The disposal scheme is a combination of tunnel- launder (chute)-pipeline designed to accommodate tailings disposed of in 20 years of mining operations. The mines' discharge systems will be connected by tunnels that merge in a common area. The tailings will then be conveyed by pipelines and launders to the sea. The system, which will serve six mines, will start from a common point to a discharge point along the sea in Lingayen Gulf, a distance of 25 km. Some of the ad- vantages of the proposal are:

1) The system will provide an area for reclamation at the disposal site in Lingayen Gulf with the possi- bility of development such as a park or a port.

2) The facilities for cleaning the pipeline/launder along the common line would be a source of irri- gation water for farmlands along the route of the common line.

3) The system would take care of future expansions and new mines within the mining district and it would have a 20-year life.

The disadvantage of the proposal is its high cost esti- mates. The rate of amortization is unacceptable to

Mining Pollution in the Philippines 341

some mines which will shoulder a part of the costs. The total construction cost estimate of this system when it was proposed in 1978 was US $60 million: $29 million for the land portion and $31 million for the sea portion.

United Nations Environment Programme (UNEP) Proposal

The disposal scheme is a combination of tunnel- launder-pipeline system of which the end-point dis- posal of the tailings is in a nearby mountain foothills valley. The advantages of the system are the following:

1) It would use state-owned lands, thus significantly lowering the costs and the litigation that could be anticipated in the expropriation of private lands.

2) The discharge area is near the mines, hence costs are lower for railings conveyance works.

3) Because of good location and the availability of roads and power lines, the disposal area offers good opportunities for development and sale.

4) It would create an aesthetically and environmen- tally acceptable area from what is presently consid- ered a desolate and economically unproductive area.

On the other hand, the feasibility of the proposal de- pends on the ability to safely contain the Bued River in the proposed containment channel at full flood so that the water will not breach the banks of the channel. This proposal will also condemn the Bued River, and the lifespan of the project is relatively short (10 years).

National Power Corporation (Philippines) and Electro-Consult (Italy) Proposal

In 1979, the Philippines' National Power Corpora- tion and ELC (Italy) proposed that the mine tailings be trapped in a multipurpose reservoir to be constructed downstream of the mines. This was in connection with a government plan to construct the huge San Roque Multipurpose Project in the Lower Agno River to pro- vide irrigation, hydroelectric power, flood control, and water quality improvement. Together with the natural erosion runoff, the mine railings will be trapped in the reservoir. Baguio Mining District lies within the imme- diate watershed of the proposed multipurpose reser- voir.

The proposed disposal scheme dictates that railings will be discharged directly from the mines to the tribu- taries of the Agno River. The tailings will accumulate in the upstream side of the proposed multipurpose reservoir. According to the proponents, the system has the following advantages:

1) The reservoir can provide up to 1.3 billion m 3 of storage and has ample capacity to impound the expected volume of mine railings without the need of tailing dams.

2) It will improve downstream water quality by elimi- nating the solids discharged by the mines and by diluting the chemicals released after mine pro- cessing.

3) Estimations based on the present mine operations indicate that the system can accommodate all mine railings production for the entire productive life of the mines (up to 40 years).

However, under this proposal, only mines affecting the Agno River would be relieved of the tailings dis- posal problems. Because of high cost estimates, the rates of amortization will be very high. The total cost of constructing the entire multipurpose project was es- timated to be US $1.2 billion (1983 prices).

While these proposals are being considered, the mining companies are resorting to their usual means of disposal, the use of existing pond-tailing dams, which is considered inadequate.

Mine Tailings and the San Roque Multipurpose Project

The proposals done by JICA and UNEP had long been forwarded to the nation's economic planning body, the National Economic Development Authority (NEDA), for deliberation and comments. Meanwhile, the Philippine government had already committed it- self to the construction of the San Roque Multipur- pose Project with the help of Japanese financing.

As one of the purposes of the project, the proposed reservoir will be used as a trap for mine railings and sediments from natural erosion. The technical feasi- bility study (NPC-ELC 1979) assumed the status quo ante of the watershed would continue, that is, the in- flow of water and silt and sediment would be the same in quality and quantity as observed in the past. How- ever, this assumption is doubtful, because soil erosion in the area is considered serious owing to the deterio- rating conditions of the watershed (BFD 1984). Also, mine tailings production will increase when the inac- tive mining concessions are developed.

The high investment cost of the SRMPP prompted Briones (1985) to attempt to quantify the effects of sedimentation on the proposed reservoir. To estimate the potential economic loss under the scenario as de- picted in the feasibility study, the rate of net sediment inflow from the mine tailings and natural erosion into the proposed reservoir has been calculated.

342 N.D. Briones

On the basis of estimations of the productive life- span of the active mines in the area and the daily ton- nage of mine tailings production, a total of 184 million m s of mine railings has been calculated to accumulate in 50 years (the economic planning period of the SRMPP). Sedimentation from natural erosion must be added to the mine railings to get the total amount of sediment that will go into the proposed reservoir. Nat- ural erosion includes gully and sheet erosion as well as erosion due to road construction and maintenance, shifting cultivation and other agricultural activities, and logging operations. Based on erosion studies con- ducted in the Agno River watershed a net erosion rate of 6500 ma/km2/year was used in the calculation (Briones 1985, BFD 1984, Abernathy 1984). Estima- tion of natural erosion gave a total volume of 168 MCM. Summing up the contribution of mine tailings and the sediment from natural erosion will give a total volume of 352 MCM for 50 years.

The accumulation of this great amount of sediment in the reservoir will reduce the outputs of hydroelec- tric energy, usable irrigation water, and storage for flood control. The computation of economic loss by Briones (1985) showed that sediments could reduce the project benefits by as much as 12% of the original estimates presented in the feasibility study. In mone- ta W terms, the value of this decrease is about US $370 million (discounted at 10%). About 52% of this amount (US $192.6 million) can be attributed to mine tailings (on the basis of the proportionate volume of mine tailings and natural erosion to be trapped in the reservoir). When this loss (or benefits forgone) is com- pared with the JICA proposal, which will cost only US $37 million (discounted at i0%), it is evident that the Philippine economy is better off if the JICA proposal is adopted as the alternative disposal scheme.

An Immediate Answer

The proposed disposal schemes are very costly to implement and are not forthcoming, but there are measures that can be employed to curb the problem. The mining firms can stabilize and reinforce the ex- isting tailings dams through vegetative covering. Sev- eral methods of stabilizing tailings dams have been tried, and vegetative covering seems to be the most practical and economical alternative for the mining companies. Introduction of vegetation to immediately provide protective cover is very essential, considering the hydrologic and ecological enhancement these plant covers can provide. The use of some biological struc- tures in stabilizing tailings dams and road banks had

been tried in the Agno River watershed by the R P- German Training Center for Reforestation and Soil Erosion Control (Costales and Costales 1983, Costales and others 1981 and 1982).

A two-year data base on mine waste revegetation by Pefiafiel (1981) revealed that Alnus maritima, Trema orientale, Pinus insularis, Desmodium sequiax, Eclipta alba, and Miscanthus sinensis are suitable for mine wastes planting in the Baguio district. Because of high mois- ture stress in mined waste areas, Orr (1975) suggested that crosswind furrowing and mulching must be adopted in order to conserve available moisture for the plants and in some degree control soil erosion and gushing overland flow. Chapman (1967) recom- mended that when tree-planting on open-cast mined lands is to be done, cavities should be filled and dumps leveled before the area is covered with topsoil. Then plants of hardy pioneer species should be planted in holes to be filled with topsoil originally covering these lands. Whenever a vegetative cover is to be reestab- lished, the plants or cuttings nmst be set densely enough to be able to close up quickly to form a protec- tive blanket, which should consist of a mixture of trees, shrubs, and some grass species. Brushwoods could also be used for contour planting to temporarily arrest sur- face runoff and soil movement (Agpaoa 1975, Hudson i973).

Discussion and Conclusions

The problem of mining pollution in the Baguio Mining District will surely be felt for as long as the mining firms are allowed to operate in the area. Tradeoffs will have to be made inasmuch as many so- cial and economic benefits are involved, both for the mining industry and the downstream sector. It is nec- essary to maintain a balance between economic growth and environmental quality. What is the appropriate tradeoff between economic growth and environmental quality? The answer is crucial for setting appropriate environmental standards and for correctly allocating scarce resources between economic production and environmental protection.

The attainment of a good environmental quality is a responsibility of both the public and the private sectors. Cooperation between the mining firms and the government is needed to promote the efficient uti- lization and disposition of resources. Government poli- cies must include practical considerations and eco- nomics, but they must also include environmental pro- tection goals. Mining firms, on the other hand, must be continuously conscious of the pollution that they

Mining Pollution in the Philippines 343

contribute to the env i ronment and should endeavor to minimize the resultant ecological imbalance. T h e rate of deve lopment must balance the national economic needs and the necessity of maintaining a healthy envi- ronment .

Uncertainties cloud the solution r ecommend ing a p lanned i m p o u n d m e n t of all mill tailings into the pro- posed mul t ipurpose reservoir. The re is a need to as- sess the short- and long- term quality o f the reservoir 's water with the introduction of mill wastes. Considering the large volume of mine tailings to be eventually d u m p e d in the p roposed reservoir, there may be un- known effects on the stored water 's aquatic life, influ- ences on the water 's potential use as irrigation water, and effects on the operat ion and maintenance of the electromechanical equ ipment of the hydroelectric power plant. Since the mul t ipurpose project's main justification is o ther than as a disposal site for mine tailings, it would be appropr ia te and economic that mine tailings disposal be addressed in other ways so as not to jeopard ize the huge investment to be poured into this project.

Acknowledgments

T h e au thor is g r a t e fu l for the financial suppor t provided by the Envi ronment and Policy Institute, E a s t - W e s t Cen{er, Honolulu, Hawaii, USA. Sincere appreciat ion is ex tended to the staff o f the Watershed Managemen t Group of the National Power Corpora- tion, Diliman, Quezon City, the Philippines, for pro- viding logistical suppor t dur ing the field study.

Literature Cited

Abernathy, C.L. 1984[ Ambuklao Reservoir, Philippines: comments on sedimentation rates. Consultant report, Na- tional Power Corporation, Quezon City, The Philippines.

Agpaoa, A.C. 1975. Manual for reforestation and erosion control for the Philippines. German Agency for Technical Development, Eschbarn, Germany.

BFAR. 1983. Report on the pre-impoundment survey of Lower Agno River (San Roque Dam) Pangasinan on Au- gust 25-30. Memorandum report, Bureau of Fisheries and Aquatic Resources, Quezon City, The Philippines.

BFD. 1984. Annual report. Bureau of Forest Development, Ministry of Natural Resources, Quezon City, The Philip- pines.

BMG. 1983. Situationer report on the pollution problem caused by mining operations in the Philippines. Bureau of Mines and Geosciences, Ministry of Natural Resources, Manila, The Philippines.

Briones, N.D. 1985. Socioeconomics of watershed manage- ment: the case of the Lower Agno River watershed, Luzon,

Philippines. PhD dissertation, University of Hawaii, Hono- lulu, Hawaii.

Bugnosen, E.M. 1981. Mine pollution. Paper presented at the 1979-1980 international course on environmental science, Delft, The Netherlands.

Chapman, C.W. 1967. A manual on establishment tech- niques in man-made forests. Paper presented on FAO symposium on man-made forests, Canberra, Australia.

Costales, E. F., Jr., and A. V. B. Costales. 1983. Effects of plant combinations upon protection/stabilization of mined waste areas. Terminal report of PCARRD Project no. 639. Forest Research Institute, Baguio City, The Philippines.

Costales, E. F., Jr., A. V. B. Costales, and A. C. Bravo. 1981. Methods of revegetating mined waste areas through dif- ferent soil amendments. Research terminal report, Forest Research Institute, UPLB, College, Laguna, The Philip- pines.

Costales, E. F.,Jr., A. V. Lopez, and G. Felipe. 1982. Restora- tion of surface and mined waste areas by selected vegeta- tive engineering methods. Research terminal report, Forest Research Institute, UPLB, College, Laguna, The Philip- pines.

Gaddi, I.C. 1981. Environmental management on mineral resources development in the Philippines. Bureau of Mines and Geophysics, Ministry of Natural Resources, Manila, The Philippines.

Holme, N. A. 1978. Environmental management of mineral wastes. Sijthoff and Noordhoff, Alpen van den Rijn, The Netherlands.

Hudson, N. 1973. Soil conservation. Cornell University Press, Ithaca, New York.

Mantell, C.L. 1975. Solid wastes, origin, collection, pro- cessing, and disposal. John Wiley and Sons, New York, New York.

Mercado, B. T. 1974. Study of the growth of some rice vari- eties in NaC1 + salinated soils as affected by season. Philip- pine Agriculturist 58:40-49.

NEDA. 1985. Philippine statistical yearbook. National Eco- nomic Development Authority, Manila, The Philippines.

NEEP. 1983. Environmental situationers: Inventory of envi- ronment-related projects. National Environment Enhance- ment Program, University of the Philippines, Diliman, Quezon City, The Philippines.

NIA. 1978. Mine tailings and its effects on NIA irrigation systems: an overview. National Irrigation Administration, Quezon City, The Philippines.

NIA. 1983. Project profile, SRMPP irrigation component. National Irrigation Administration, Quezon City, The Phil- ippines.

NPC-ELC. 1979. San Roque multi-purpose project feasibility study: main report. National Power Corporation, Manila, The Philippines.

Orr, H.K. 1975. Mine spoil reclamation research at Bella Ayn Mine, northeast Wyoming. Pages 304-307 in Sympo- sium proceedings, Fort Union Coal Field, vol. 3. Reclama- tion Section.

Pefiafiel, S. R. 1981. Reclamation of mine tailings/mine waste

344 N.D. Briones

through vegetation establishment. Research Report PCARR Project no. 1123. PCARR, Laguna, The Philip- pines.

Peters, T. H., and H. Kitching. 1978. Report to the Govern- ment of the Philippines on mine tailings disposal in the Baguio area: Agno and Bued river systems. United Na- tions Environment Programme, Manila, The Philippines.

Saddam, T. A., and G. H. Prospero. 1963. Sedimentation in- vestigations in the Agno River basin by the Bureau of

Public Works. Paper presented for the world power con- ference and congress of large dams, first technical sympo- sium, Manila, The Philippines.

Sulliven, G. 1967. Current research trend in mined-land con- servation and utilization. Mining Engineering 19:63-67.

Villavicencio, E. T. 1977. The mineral industry and the envi- ronment. Paper presented at the 5th symposium on min- eral resources development and the 24th mine safety con- ference, 24-26 November, Baguio City, The Philippines.