November-December 2008
A mess of mines

A mess of mines

CLOSING DOWN a mine is not just a matter of giving employees their walking papers and putting a padlock on the door. Indeed, when a mine ceases operations, a full-blown cleanup (plus sometimes an orderly dismantling) follows. Or at least that is what should happen.

Over the last three decades, several large-scale mines in the country have been shut down because of economic loss, labor disputes, or a rejected mining application. But none of these mines was rehabilitated right after closure; unfortunately, government regulations at the time lacked the provision to enforce remediation. Those regulations came in 1996, when guidelines on mine rehabilitation and decommissioning were set in the implementing rules and regulations of the Mining Act of 1995.

To date, though, only one abandoned mine is undergoing rehabilitation. And while Mines and Geosciences Bureau (MGB) officials say a few other idle mines have attracted lease applications (and presumably would be checked and fixed up at some point), there is no question that these and others like them pose health and environmental risks – and will continue to do so until their various problems are addressed.

Black Mountain mine facility in Tuba, Benguet. [Photo courtesy of Tetra Tech EM Inc.]

In fact, a 2001 report by Tetra Tech EM Inc. on 20 abandoned mines across the country had observed that all pose risks at varying degrees. Noted the U.S.-based environmental consultancy firm: “Land and water media are impacted with chemical contaminants, which may harm human health and the aquatic, terrestrial and wild lives. Unless proper mitigation and corrective actions are undertaken, the surrounding population and receiving environment will be continuously exposed to both chemical and physical risks.”

MGB had tapped Tetra Tech to help it draw up a list of mines that needed the most attention. In its report, Tetra Tech said that most of the 20 mines it was asked to assess failed to meet the official criteria for total suspended solids (TSS), total dissolved solids (TDS), and the measure of acidity or alkalinity (pH). Most also failed to comply with the United States Environmental Protection Agency standard for freshwater sediments, indicating the accumulation of metal contaminants in the receiving bodies of water.

Previously, MGB had conducted a similar study, but that one assessed 44 abandoned mines.

MGB pinpointed six mines from the Tetra Tech report that it said would take priority in rehabilitation efforts. These had been run by the following companies: Philippine Pyrite Corp. in Bagacay, Western Samar; Palawan Quicksilver Mines in Puerto Princesa City; Basay Mining Corp. in Negros Oriental; Consolidated Mines Inc. in Marinduque; and Thanksgiving Mine/Benguet Exploration Inc. and Black Mountain Inc. in Benguet.

Heavily-rusted mine facilities at the Benguet Corporation-Dizon Copper/Gold Mines (BCD) in San Marcelino, Zambales. [Photo courtesy of Tetra Tech EM Inc.]

From the earlier study, it selected the mine operated by Western Minolco Corp. in Benguet for the last slot in its priority list. Among other things, the MGB said that the mine had caused the destruction of aquifers, while toxins were found in surrounding bodies of water.

IT IS the Philippine Pyrite mine in Bagacay that is now undergoing rehabilitation. Yet while it says it will still use the Tetra Tech study as a reference point, the MGB has started re-evaluating and revising its priority list of abandoned mines for rehabilitation, based on an entirely new set of criteria and processes.

For sure, even Tetra Tech had confessed having difficulties over what constitutes an “abandoned mine.” Abandoned areas usually refer to areas with no claimant at all, but the firm noted that although many mines had ceased operations, several still have owners and even managers.

A case in point is the controversial Marcopper mine in Marinduque, which has not been in use since it had a monumental mine-tailings spill in 1996. The company that owns it still exists, and guards remain there to secure the premises. The MGB also says that it did not include it in any of its risk assessment studies primarily because of ongoing court proceedings.

At least there is an action plan for the Marcopper cleanup, although that has been on standby for the last three years. Besides that of Philippine Pyrite, the rest of the mines the MGB had on its old list have neither that nor the chance of being rehabilitated anytime soon — unless new owners step in and do the cleanup themselves. That means a wait that may not be welcome to the communities living within or near the six other former “priority” mines, since they will bear the brunt of any calamity coming from these sites. (see Table 1)

Table 1: Risky Group — MGB’s First List of Priority Abandoned Mine Sites
Source: Semi-Detailed Assessment of 20 Abandoned/Inactive Mine Sites In The Philippines, Tetra Tech EM Inc. (2001) Information on Western Minolco Corp. is based on previous published reports.
n.a. — not available
Rate of risk is based on the Risk Based Prioritization Strategy. Refer to Table 2.

Philippine Pyrite Corporation Pyrite, Copper Bagacay, Hinabangan, Western Samar 1956–1992 82.53
  • Dilapidated mill and laboratory facilities may collapse and cause harm.
  • Steep slopes in Mine Pit #1 are unstable and may cause erosion.
  • The walls of tailings ponds 1, 6, 7 and 8 may collapse and cause spillage of its contents.
  • The remaining walls of tailings ponds 2,3,4 and 5 may give way and cause landslides, flash floods and mudslides.
  • The continuing discharge of tailings is causing siltation of the drainage systems.
Palawan Quicksilver Mines Mercury Tagburos, Puerto Princesa, Palawan 1953–1976 80.23
  • No observed physical hazards
Basay Mining Corporation Copper Bgy. Maglinao, Basay, Negros Oriental 1978–1994 79.79
  • The tailings ponds are unstable.
  • Unstable slopes are prone to erosion and landslides.
  • Potential accidents may happen in the abandoned mine and mill facilities due to unstable structures.
Consolidated Mines Inc. Copper Ino and Capayang, Mogpog, Marinduque 1977–1979 61.93
  • The open mine pit is water-filled.
  • Metal and iron scraps, spent/unused chemicals, corroded drums, roofing and wall panels, including equipment and machinery were left scattered in the mill plant area.
Black Mountain Inc. Gold Tuba, Benguet n.a. 59.86
  • No observed physical hazards
Thanksgiving Mine, Benguet Exploration, Inc. Gold Camp 6, Kennon Road, Tuba, Benguet n.a. 59.86
  • No observed physical hazards
Western Minolco Corp. Copper Atok, Benguet 1974–1982 n.a.
  • n.a.

In truth, having families near the mine sites had been one of the key factors on which MGB based its selection of the seven mines for priority rehabilitation. Thus, even if Tetra Tech had ranked others higher in terms of risk, those mines were excluded from the MGB list because they were deemed far enough from any household for the dangers they posed to have immediate impact.

To make its assessment, Tetra Tech had used a Risk Based Prioritization Strategy (RBPS) that considered four major criteria: waste generation and management, pathways, receptors, and compliance. The higher the score a mine got, the higher the risks it presented. (see Tables 2 and 3)

Table 2: Criteria Codigo — Tetra Tech’s Risk Scorecard
Source: Tetra Tech

Waste Generation and Management Airborne
Subtotal 33
Pathways Air
Solid and Liquid
Subtotal 21
Receiving Media/Receptors General
Surface Water
Other Ecological
Social Environmental
Subtotal 34
Compliance Violations
Number of Valid Complaints
Subtotal 12

The Philippine Pyrite mine in Bagacay, which topped the MGB list, garnered a risk rate of 82.53 percent in the Tetra Tech study. It ranked second among the 20 mines that Tetra Tech looked into, the top slot being occupied by Benguet Corporation-Dizon Copper/Gold Mines (BCD) in San Marcelino, Zambales, which scored 83.93 percent. The BCD mine had no community residing anywhere near its mine site, hence its exclusion from the MGB list.

The Philippine Pyrite mine, which extracted pyrite and copper for 36 years, is now the government’s flagship mine-rehabilitation project. The Mining Environment and Safety Division (MESD) of the MGB has pointed out that the mine not only exhibits many environmental problems, it is also located at the border of a nature reserve.

The threats at the Philippine Pyrite mine include the formation of an acid mine drainage, which may lead to the spread of potentially toxic metals. In addition, its tailings ponds are unstable and may collapse, spilling toxic contents. Its mill and laboratory facilities are also decrepit.

Oil slick at Bued River downstream of quarrying operations at former Benguet Exploration mine site. [Photo courtesy of Tetra Tech EM Inc.]

Three of the six mines selected from the Tetra Tech study had no physical hazards, but they nevertheless made it to the MGB list because they had significant problems in other areas. Palawan Quicksilver, which mined mercury in Puerto Princesa for more than two decades, was among the three without physical hazards. Yet it apparently had considerable waste generation and management issues, scoring 29 points out of the possible 33 points in that category.

The two other mines that posed no physical risks were those of Benguet Exploration and Black Mountain. Sediment samples from these gold mines, however, showed that they exceeded screening standards for concentrations of all chemicals “of concern”: arsenic, lead, zinc, copper, and cadmium.

IN ITS report, Tetra Tech had acknowledged that a detailed rehabilitation and full implementation of engineering technology may not yet be feasible. But, it said, there are selected controls that need to be implemented especially for sites posing high physical risks to the surrounding population. These include the structural enhancement of tailings ponds and dikes to prevent collapse and contain waste rock in order to reduce acid mine drainage.

The report also highlighted the importance of understanding the source, pathway, and exposure scenario of potential contaminants. Tetra Tech recommended as well a full-blown site and ecological risk assessment after a few years of operation for a mine. This could help detect potential environmental damage early, it said.

In the meantime, MGB’s latest attempts to assess which idle mines need most attention have yielded only four mines “for further evaluation” so far: those of Atlas Consolidated Mining and Development Corporation (ACMDC)/Uldom Pit in Cebu, Hinatuan Mining Corp. (HMC) Manicani in Eastern Samar, North Davao Mining Corp. (NDMC) in Davao, and the Española mine in Palawan.

MGB’s newest assessment strategy requires each regional office to use these impact categories to gauge the level of risks presented at abandoned mines within its area: acid mine drainage hazard, safety hazard, impact to vegetation, erosional hazard, visual intrusion, and heritage value. MGB would then compile and evaluate each region’s assessment results to come up with a new list of mines to rehabilitate.

Choosing which mine to rehabilitate and how to go about that task have proved difficult and daunting, the MGB says. For instance, explains MESD engineer Marcial Mateo, each plan must be site specific, depending on the type of mine. And this takes a great deal of time, he says.

As for idle mines that now have lease applicants, Mateo admits that there is no way of knowing if those who have expressed interest in the mines would eventually assume responsibility over the environmental liabilities they would inherit. This is why, he says, the government is now considering the inclusion of rehabilitation and/or environmental liabilities as conditionality in lease applications for abandoned mines.

Mateo says that another option is to require the investor to pay the government for whatever expenses it would incur for the rehabilitation and remediation of a mine site. But whether or not there is an application to reopen an abandoned mine, he says, an in-depth evaluation of the current condition of the mines must be done.

Interestingly, for all the dangers posed by the abandoned mines, people interviewed by Tetra Tech for its report had called for their reopening. After all, these had provided employment for residents of the host communities when they were in operation, as well as for those in nearby areas. Mining companies were seen as stable sources of income compared to farming and fishing, which were among the more common means of livelihood of towns that also had mining sites.

Now if only someone would clean up the mess afterward.