Fossil Hunting at Filon 12 Vanadinite Fossil Mine Mibladen

Introduction

Filon 12 is a decommissioned lead and vanadium mine in the Mibladen mining district, located in the Moulouya Valley south of Midelt in central Morocco. The mine is internationally known among mineral collectors for producing vanadinite crystals of exceptional quality, the hexagonal orange-red lead vanadate that has become one of the most collected Moroccan minerals worldwide. The site also preserves Devonian-age fossils in the sedimentary host rock exposed by mining activity, including trilobites and brachiopods in the limestone horizons adjacent to the ore bodies. A visit to Filon 12 therefore offers the unusual combination of world-class mineral collecting alongside Paleozoic fossil material, set in an evocative post-industrial mining landscape at the foot of the High Atlas Mountains.

This guide covers the geology of the Mibladen district, the vanadinite and fossil specimens found there, how to reach Mibladen from Midelt and Errachidia, and the arrangements required for a visit to the Filon 12 area.

Vanadinite - ACF mine, Mibladen, Morocco.jpg. Photo: Ivar Leidus via Wikimedia Commons (CC BY-SA 4.0)

Location and Getting There

Location

Mibladen is located approximately 25 km south of Midelt in the Draa-Tafilalet region of southeastern Morocco, in the Moulouya River valley between the High Atlas and the Saharan platform. Midelt sits on the N13 highway between Errachidia (170 km southeast) and Khenifra (170 km northwest). The Filon 12 mine workings are on the hillside above Mibladen village, accessible via a rough track from the village. GPS coordinates for Mibladen village are approximately 32.60°N, 4.63°W.

Getting There

From Midelt, take the road south from the center of town toward Mibladen, a distance of approximately 25 km on a paved road through the Moulouya Valley. The journey takes about 30 minutes. From Errachidia, head north on the N13 to Midelt (approximately 170 km, 2 hours), then south to Mibladen as above. From the village, the mine site is reached by a rough track ascending the hillside; a 4WD vehicle or on-foot approach is recommended for the final section. Local guide services in Mibladen and Midelt can arrange transport and site access. The mineral dealers in Midelt, who sell Filon 12 vanadinite specimens, are a good starting point for guide referrals.

What You'll Find

Vanadinite crystals are the primary draw for most visitors. Vanadinite, Pb5(VO4)3Cl, occurs as short hexagonal prismatic crystals ranging from bright orange-red to deep ruby red, typically 1 to 25 mm in length. The Filon 12 material is noted for crystals on matrix showing good form with flat terminations, sometimes in barrel-shaped modifications. Specimens show well-defined crystal faces and a high luster. The best Filon 12 vanadinite came from a specific productive period of mining in the mid-to-late twentieth century; specimens currently available are mostly from accumulated dealer stock and ongoing small-scale surface collecting near the old workings.

Trilobites from the Devonian limestone host rock include Phacops-grade forms and fragmentary phacopid material, typically found as disarticulated exoskeletal elements rather than complete specimens. The condition is generally inferior to the trilobite material from dedicated Devonian quarry sites such as Boutchafine, because the limestone at Mibladen was not systematically worked for fossils and most fossil-bearing rock was processed as ore or spoil.

Brachiopods, primarily spiriferids, occur in the sedimentary horizons surrounding the ore bodies. Occasional crinoid columnals and coral fragments complete the Devonian assemblage. The fossils are secondary to the minerals at this site and best treated as a complement to the collecting experience rather than the primary objective.

Additional minerals associated with the oxidized zone of the deposit include mimetite (yellow to yellow-green hexagonal crystals similar in form to vanadinite), wulfenite (tabular orange-yellow molybdate crystals), and occasional cerussite. These occur as minor associates and are less consistently available than vanadinite.

Geologic History

The Ancient Environment

The sedimentary host rocks at Mibladen are Devonian carbonates deposited approximately 395 to 370 million years ago on the Gondwana shelf, in the same broad marine system that produced the trilobite-bearing limestones of the Tafilalet region. The Mibladen area was subsequently affected by hydrothermal ore-forming processes related to Mesozoic and Cenozoic igneous activity and tectonic uplift. Lead-rich hydrothermal fluids migrated through fracture networks in the Devonian carbonates and deposited galena and other primary ore minerals. Later oxidation of the primary sulfide ore body by percolating groundwater converted galena (lead sulfide) to secondary lead minerals including vanadinite (incorporating vanadium from the surrounding rocks), mimetite, and cerussite, producing the spectacular mineral assemblage for which Mibladen is known.

How Filon 12 Became a Collecting Site

The Mibladen district was mined for lead by various operators from at least the early twentieth century under French colonial administration. The Filon 12 ore body was one of several veins worked in the district. Mining operations wound down as ore grades declined, leaving the mine workings, spoil heaps, and mineral-bearing oxidized zone accessible. Local mineral collectors and dealers recognized the quality of the vanadinite specimens emerging from the oxidized ore and began systematic surface and small-scale underground collection. By the 1970s and 1980s, Mibladen vanadinite had become one of the most recognized Moroccan mineral specimens in international collections. The site's combination of mineralogical and paleontological interest makes it a worthwhile stop for collectors with broad interests.

Visiting and Collecting Information

Access and What to Expect

The Filon 12 area is a tour-only site; independent access to active collecting areas and mine workings requires local guide arrangements. Guide services in Mibladen village or through dealers in Midelt can arrange access for approximately 300 to 500 MAD (30 to 50 USD) per person for a half-day visit. At the site you can collect vanadinite on matrix from accessible oxidized zone exposures and spoil material, and inspect the Devonian limestone faces for fossil material. Prepared vanadinite specimens of higher quality are available for purchase from Mibladen and Midelt dealers.

Moroccan customs regulations permit tourists to export mineral specimens and up to approximately 10 fossil specimens for personal non-commercial use. Given the mineral-specimen focus of most Filon 12 visits, retain documentation for any significant vanadinite purchases.

What to Bring

Bring at least 2 liters of water per person. The Moulouya Valley can be cool in winter (temperatures below 0°C at altitude) and hot in summer. Layered clothing is sensible year-round. Sturdy boots are essential on the rocky mine terrain. Safety glasses are required near any mine workings. A geology hammer and sturdy collecting bags are useful for matrix specimens. Bring cash in dirhams. A loupe is valuable for examining crystal structure on vanadinite specimens.

Safety and Practical Tips

Do not enter any underground workings without appropriate lighting, a guide, and confirmation that the tunnel is stable. Old mine workings can have unstable roofs, poor air, and misleading layouts. Surface spoil areas and open oxidized zone exposures are safer and more productive for casual visitors. The mineral dealers in Midelt town are a reliable source for Filon 12 vanadinite without the risks of self-collecting at the mine: the selection is broader, the specimens are cleaned and mounted, and the prices are comparable to what you would pay a guide to take you to the site. A combination of a mine visit for context and dealer shopping in Midelt for final purchases makes the most efficient use of time.