@prefix owl:   <http://www.w3.org/2002/07/owl#> .
@prefix ssd:   <http://www.w3.org/ns/sparql-service-description#> .
@prefix xsd:   <http://www.w3.org/2001/XMLSchema#> .
@prefix skos:  <http://www.w3.org/2004/02/skos/core#> .
@prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#> .
@prefix qb:    <http://purl.org/linked-data/cube#> .
@prefix dgu:   <http://reference.data.gov.uk/def/reference/> .
@prefix ui:    <http://purl.org/linked-data/registry-ui#> .
@prefix dct:   <http://purl.org/dc/terms/> .
@prefix reg:   <http://purl.org/linked-data/registry#> .
@prefix api:   <http://purl.org/linked-data/api/vocab#> .
@prefix dcat:  <http://www.w3.org/ns/dcat#> .
@prefix vann:  <http://purl.org/vocab/vann/> .
@prefix prov:  <http://www.w3.org/ns/prov#> .
@prefix foaf:  <http://xmlns.com/foaf/0.1/> .
@prefix cc:    <http://creativecommons.org/ns#> .
@prefix void:  <http://rdfs.org/ns/void#> .
@prefix org:   <http://www.w3.org/ns/org#> .
@prefix odrs:  <http://schema.theodi.org/odrs#> .
@prefix env-ui: <http://environment.data.gov.uk/registry/structure/ui/> .
@prefix hike:  <https://data.geoscience.earth/ncl/def/hike/> .
@prefix version: <http://purl.org/linked-data/version#> .
@prefix dbo:   <http://dbpedia.org/ontology/> .
@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ldp:   <http://www.w3.org/ns/ldp#> .
@prefix time:  <http://www.w3.org/2006/time#> .
@prefix vs:    <http://www.w3.org/2003/06/sw-vocab-status/ns#> .
@prefix dc:    <http://purl.org/dc/elements/1.1/> .

<https://data.geoscience.earth/ncl/DrillingMethod/airCore>
        a                  skos:Concept ;
        dct:source         <https://en.wikipedia.org/wiki/Drilling_rig#air_coreDrilling> ;
        skos:definition    "Air core drilling and related methods use hardened steel or tungsten blades to bore a hole into unconsolidated ground. The drill bit has three blades arranged around the bit head, which cut the unconsolidated ground. The rods are hollow and contain an inner tube which sits inside the hollow outer rod barrel. The drill cuttings are removed by injection of compressed air into the hole via the annular area between the innertube and the drill rod. The cuttings are then blown back to surface up the inner tube where they pass through the sample separating system and are collected if needed. Drilling continues with the addition of rods to the top of the drill string. Air core drilling can occasionally produce small chunks of cored rock."@en ;
        skos:notation      "6"^^xsd:ID ;
        skos:prefLabel     "air core"@en ;
        skos:topConceptOf  <https://data.geoscience.earth/ncl/DrillingMethod> .