Fertiliser specification Former Circuit Judge Michael Comyn, 9 Northbrook Road, Leeson Park, Dublin, has had a complete specification accepted by the Patents Office, dealing with the production of a fertilisers by “mixing rock phosphate with a calcareous shale carrying sulphur, iron, phosphataes, silica and aluminia, such as found in Co, Clare”. Can you elaborate?

Thought for 1m 43s

Michael Comyn (1871–1952) was an Irish barrister, nationalist politician, Fianna Fáil senator (1928–1936), and Circuit Court judge (appointed in 1936 to the Eastern Circuit). Beyond his legal and political career, he was an amateur geologist with a keen interest in mineral resources, particularly in his native County Clare. He is notably credited with discovering and initially exploiting phosphatic shale deposits in the region, which tied directly into efforts to produce fertilizers amid global supply challenges, especially during the interwar period and World War II.The patent specification you referenced appears to stem from around the 1920s (likely 1924–1925, based on historical timelines), when Comyn secured acceptance from the Patents Office (likely the British or Irish Patents Office, as Ireland’s independent patent system was established in 1927). It described a straightforward process for fertilizer production: blending rock phosphate (a common source of phosphorus, typically apatite minerals like fluorapatite) with a specific type of calcareous shale (shale rich in calcium carbonate) sourced from County Clare. This shale naturally contains supplementary elements including sulphur (often in pyritic forms), iron (e.g., from iron sulfides), additional phosphates, silica (SiO₂), and alumina (Al₂O₃).

Key Aspects of the Method and Its Context

• Process Details: The invention focused on simple mixing of the two materials, without specifying advanced chemical reactions in the public descriptions available. However, the composition suggests practical benefits:
  • Rock phosphate provides the primary phosphorus (P) for plant nutrition, essential for root development, energy transfer, and crop yields.
  • The calcareous shale from Co. Clare adds value as a multi-nutrient amendment. Sulphur aids in soil acidification and plant protein synthesis; iron supports chlorophyll production; extra phosphates boost overall P content; silica improves soil structure and plant resilience; and alumina contributes to clay-like properties for nutrient retention.
  • This blend likely aimed to create a more balanced, slow-release fertilizer compared to pure rock phosphate, which can be less bioavailable without processing. The calcareous nature (high lime content) could help neutralize acidic soils common in Ireland, while the sulphur and iron might facilitate natural oxidation processes to enhance solubility over time.
  • No heating, acidification, or complex machinery is mentioned in the specification snippet, distinguishing it from modern superphosphate production (which uses sulfuric acid). It may have been intended as a low-cost, local alternative using readily available Irish resources.
• Geological and Regional Background: The shale in question is from phosphatic deposits in areas like Noughaval and Toomullin (near Doolin) in north County Clare. These are part of the Carboniferous limestone and shale formations in the Burren region, where karst landscapes expose mineral-rich layers. Comyn, based in Lisdoonvarna (Co. Clare) during parts of his life, identified these in 1924 as an amateur geologist. The deposits were economically viable due to their phosphate content (up to 20–30% P₂O₅ in some analyses), supplemented by the other minerals noted.
• Historical Development and Implementation:
  • Early Operations (1924–1939): Comyn extracted initial test batches (50 tons in 1924, 100 tons in 1925) and secured planning permission for an opencast quarry at Noughaval. This site operated briefly but closed by 1933 due to rising overburden removal costs and competition from higher-grade imports. He then shifted to a richer site along the Aille River in Doolin, mining directly from the riverbed and adjacent land. This disrupted local hydrology, causing river water to sink into underlying caves (part of the Doolin Cave System), altering flows permanently.
  • World War II Takeover (1939–1947): With global phosphate imports from North Africa and South America cut off, the Irish government (via Mianrai Teoranta, a state mining company) compulsorily acquired the operations in 1939 to bolster domestic fertilizer production for agriculture. Comyn was promised royalties, but a dispute led to litigation (rumors of a £50,000 award, though unconfirmed). Underground mining expanded, with adits, shafts, and pillar-and-stall methods extracting a ~1-meter-thick phosphate bed. At peak, it employed nearly 700 workers, but a 1940s fatal accident (due to faulty winching) highlighted safety issues. Output focused on raw phosphatic material for fertilizer, but high processing costs (£3/ton) led to closure in 1947 as imports resumed.
  • Legacy and Outcomes: The mines supplied critical fertilizers during wartime shortages, supporting Irish food security. Post-closure, sites were landscaped, leaving ruins like compressor houses and rail lines. Environmentally, the operations impacted karst ecosystems, but no major long-term pollution is noted. Comyn’s work pioneered local resource use, though it remained small-scale compared to global phosphate industries.

This patent and mining venture reflect Comyn’s blend of legal acumen and geological passion, contributing to Ireland’s early 20th-century push for self-sufficiency in agriculture. If this refers to a specific newspaper clipping or document (e.g., from the Irish Times or similar, circa 1920s), it may have been publicized to attract investment. For exact patent text, consulting Irish Patent Office archives (now Intellectual Property Office of Ireland) or historical databases like Espacenet could yield the full specification under his name.

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