Abstract: A pressure control apparatus includes a main line section and a branch line operably joined to and extending from the main line section. A housing around the branch line has a first wall and a second wall opposed to the first wall, and a first opening is in the first wall. A plug is operably positioned in the branch line, and the plug has a first position that prevents fluid flow through the branch line and a second position that permits fluid flow through the branch line. A loop extends from the plug, and a lever pivotally connected to the second wall and extending through the loop and the first opening in the first wall positions the plug to the first and second positions.

Abstract: A composition for treating an excavation activity includes a reagent suspended in foam to form a reagent-foam mixture. The reagent is selected to react with at least one of sulfides or bacteria in waste rock or tailings materials to reduce acid rock drainage. The reagent includes at least one of limestone, dolomite, sodium bicarbonate, steel slag, fly ash, or sodium hydroxide.

Abstract: A system for treating an excavation activity includes a distribution network in fluid communication with the excavation activity. A foaming agent and a reagent are supplied to the distribution network to form a reagent-foam mixture. The reagent is selected to react with at least one of sulfides, bacteria, or heavy metals or to coat particulate materials. A method for treating an excavation activity includes flowing a foam through a distribution network in fluid communication with the excavation activity and selecting a reagent to react with at least one of sulfides, bacteria, or heavy metals or to coat particulate materials. The method fluffier includes mixing the reagent with the foam flowing through the distribution network to form a reagent-foam mixture and dispersing the foam-reagent mixture over at least a portion of the excavation deposit.

Abstract: A system for treating an excavation activity includes a distribution network in fluid communication with the excavation activity. A foaming agent and a reagent are supplied to the distribution network to form a reagent-foam mixture. The reagent is selected to react with at least one of sulfides, bacteria, or heavy metals or to coat particulate materials. A method for treating an excavation activity includes flowing a foam through a distribution network in fluid communication with the excavation activity and selecting a reagent to react with at least one of sulfides, bacteria, or heavy metals or to coat particulate materials. The method fluffier includes mixing the reagent with the foam flowing through the distribution network to form a reagent-foam mixture and dispersing the foam-reagent mixture over at least a portion of the excavation deposit.

Abstract: A system for sampling a fluid includes a conduit having an inner surface with a substantially constant, unobstructed diameter between upstream and downstream points. A sample line having an inlet and outlet provides fluid communication outside of the conduit. An inlet port in the sample line is radially inward from the upstream point and faces substantially upstream inside the conduit. A sensor is in fluid communication with the sample line. A method for sampling a fluid includes providing fluid communication through a sample line to a conduit having an inner surface with a substantially constant, unobstructed diameter between upstream and downstream points, wherein the sample line has an inlet port radially inward from an upstream point and facing substantially upstream inside the conduit. The method further includes flowing at least a portion of the fluid through a sensor in fluid communication with the sample line.

Abstract: In-situ retorts of elongated rectangular shape in horizontal cross section are constructed in subsurface carbonaceous deposits in a plurality of parallel rows in each of which the retorts are arranged end-to-end. The rows are separated by unbroken pillars extending upwardly from rock that is not undermined or penetrated by retorts or tunnels. The ceilings of the retorts slope upwardly at an angle of at least 40.degree. with the horizontal to an apex or crown running longitudinally of the retorts to minimize the danger of roof collapse and provide a broadened pillar through which cross drifts opening into the crown of the retort extend for supplying combustion air. The crown of the ceiling is rounded to minimize concentration of the forces imposed by the overburden.

Abstract: An underground deposit of a carbonaceous material is retorted in an array of in-situ retorts arranged in a plurality of parallel rows. Each row of retorts is separated from adjacent rows by a pillar that extends unbroken for the length of the row. An apex drift extends longitudinally of each row and forms the crown of the retorts in that row. Combustion air for the retorting of the deposit in rubblized retorts in one row is supplied through the apex drift of an adjacent row. Delivery of combustion air into the crown of a retort for the retorting of the rubblized oil shale is through cross drifts from the apex drift of the adjacent row of retorts. Following combustion of the deposit in retorts in the first row, retorts are constructed and rubblized in a second row with the apex drift through which air had previously been supplied forming the crown of the retorts in the second row. Air for retorting deposit in the second row of retorts is delivered through a third apex drift.