SUBSURFACE ROTARY DRILLING INVESTIGATION SPECIFICATIONS

Transcription

1 I. SCOPE OF WORK SUBSURFACE ROTARY DRILLING INVESTIGATION SPECIFICATIONS The Department of Environmental Protection, Bureau of Abandoned Mine Reclamation requires a contractor to conduct subsurface rotary drilling investigations within the delineated project area as indicated on the Borehole Location Map. The Contractor shall furnish all labor, technical assistance, equipment, tools and material necessary to perform the Contract tasks. The work to be performed under this Contract will require non-percussion or percussion rotary drilling at a series of borehole locations. Please refer to the Project Drawing. When requested by the Department s Representative, the Contractor shall provide a completely mobilized rotary drilling rig on the project site within forty-five (45) days of being notified to proceed. The Contractor will have to move the rotary drill rig to the project site together with all necessary supporting equipment and provide air or water for drilling. The work at the site will include drilling air rotary borings for the purpose of obtaining continuous rock chip samples of bedrock. The Contractor shall furnish and install eight-inch (8 ) steel surface casing and fourinch (4 ) inside diameter PVC casing pipe, including plug and cap, in the boreholes as designated by the Department s Representative. The completion of the work at the project site will require removal of all equipment, sealing and backfilling of designated boreholes and the restoration of the surface to a condition equal to or better than that which existed prior to the start of the project work. Proposed for this project is drilling six (6) holes to accommodate four-inch (4 ) I.D. Schedule 40 PVC casing. See the table below for approximate depths of each hole. Due to the nature of the work, it might be necessary to slightly modify the tasks for a boring location while the work is being conducted. Such modifications could include: (1) relocation of boreholes, (2) deletion of boreholes, (3) addition of boreholes in the vicinity of the location, and (4) variation of the depth of the holes proposed for this project. Any modifications shall be approved and directed by the Department s Representative. Estimated Drilling Depths Hole No. Surface Elevation Bottom of Coal Elevation Drilling Footage MW MW MW MW MW MW Total 2445 Note: All elevations are estimated 1

2 The Contractor agrees to furnish all necessary labor and equipment and to perform all the work and labor required herein in an expeditious, substantial and workman-like manner. Any questions regarding these Specifications should be directed to Scott Poborsky at Any questions concerning the contracting or bidding process should be directed to Phyllis Cocco at II. CONTRACT TASKS 1. MOBILIZATION AND DEMOBILIZATION 1.1 SCOPE The work covered by this section consists of the delivery to the project area of all equipment, material and supplies, acquisition of any permits, removal from the site of all equipment after the completion of work, delivery of records, clean-up of the site and final inspection by the Department s Representative. 1.2 PROCEDURE Mobilization shall consist of the delivery to the project area of all equipment, material and supplies to be furnished by the Contractor, the complete assembly in satisfactory working order of all such equipment on the job and the satisfactory storage at the site of all such supplies. Moving between holes and setups at hole locations included under the Contract shall be incidental to the other appropriate Contract item and no separate payment will be made. Demobilization shall consist of the removal of all equipment from the project area and clean-up and restoration of any damaged areas to as good as or better condition than that which existed prior to the commencement of work. This work will include reseeding of areas designated by the Department s Representative. All equipment and methods to be used by the Contractor shall be subject to approval by the Department s Representative. However, approval of the equipment shall not be construed as approval of the performance thereof. The Contractor shall furnish any additional or special equipment necessary for him to obtain the desired end results. The Contractor, at his expense, shall obtain all permits, of whatever nature, necessary for the completion of this work, and the Contractor shall comply with all existing laws, ordinances, rules and regulations relating to his operations. The Department or its designated representative will obtain easements from property owners. Every effort shall be made to minimize damage incidental to access and drilling. Maximum use will be made of existing roads and lanes for access. Where it is necessary to deviate from roads and lanes, such deviation shall be by one (1) track, at a location causing the least damage. 2

3 The Contractor shall be liable to the property owners for any damage to vegetation, crops, and/or property, irrespective of whether the damage was caused by his negligence or was an unavoidable consequence of drilling operations. The Contractor shall be liable for any and all damage, including damages for necessary access. The Contractor shall be required to consult with property owners as to when he intends to move equipment to the drilling locations. 1.3 DELIVERY OF RECORDS The Contractor shall be responsible for furnishing the following records for the project area within the following time constraints: 1. Two (2) typed copies and electronic copies of each borehole log, no later than twenty-one (21) days after completion of all of the boreholes. Each borehole log shall provide pertinent information such as, but not limited to: 1. Borehole number. 2. Borehole completion date. 3. Depth of unconsolidated material (top of bedrock). 4. Air loss or loss of returns. 5. Rock types (description of cuttings). 6. Measured void or caved and broken zone. 7. Depth to each water bearing zone. 8. Linear feet, size, type of casing. 2. Copies of any other records kept by the Contractor, which in the opinion of the Department s Representative will aid in the interpretation of the borings, may be requested at any time during the course of the Contract. No additional payment will be made for delivery of records, since delivery is included in Contract Item, Mobilization and Demobilization. 1.4 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, will be made on the basis of a complete unit, but only to the extent directed by the Department s Representative. Payment will be made at the Contract Unit Price bid per Contract Item, Mobilization and Demobilization, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. Mobilization will be paid in the amount of forty percent (40%) of the unit price bid following complete mobilization. 3

4 Demobilization will be paid in the amount of sixty percent (60%) of the unit price bid following complete demobilization. 2. BULLDOZER MOBILIZATION AND DEMOBILIZATION 2.1 SCOPE The work covered by this section consists of mobilizing and demobilizing a bulldozer. Access to most of the boreholes will need short access routes built to borehole locations off existing right-of-ways. 2.2 PROCEDURE Authorization will be given by the Department s Representative to mobilize and demobilize a bulldozer, Caterpillar D-4 or equal size, for the construction of access routes, development of drilling sites, moving of the drill rig(s) into and out of position and regrading subsequent to drilling operations. 2.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, will be made on the basis of a complete unit, but only to the extent directed by the Department s Representative. Payment will be made at the Contract Unit Price bid per Contract Item, Bulldozer Mobilization and Demobilization, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. Mobilization will be paid in the amount of forty percent (40%) of the unit price bid following complete mobilization. Demobilization will be paid in the amount of sixty percent (60%) of the unit price bid following complete demobilization. 3. BULLDOZER WITH OPERATOR 3.1 SCOPE The work covered by this section consists of operating a bulldozer, Caterpillar D-4 or equal size. When necessary for ingress, egress or drilling, a bulldozer will be authorized by the Department s Representative. 3.2 PROCEDURE A bulldozer, Caterpillar D-4 or equal size, and operator will be utilized for access as necessary to carry on drilling activities. 4

5 3.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, will be made on an hourly basis for actual operation of the equipment, but only to the extent directed by the Department s Representative. Payment will be made at the Contract Unit Price bid per hour for Contract Item, Bulldozer with Operator and will be divided no finer than by one-half (1/2) hour increments, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. 4. DRILLING ROTARY BOREHOLES 4.1 SCOPE The work covered by this section consists of furnishing all labor, material, equipment, supplies and all necessary incidentals to drill boreholes through overburden material, rock and mined coal beds. 4.2 PROCEDURE All work shall be done under the direction of the Department s Representative. The work involves the drilling of rotary boreholes according to the Technical Specifications for the project area. The depth of the individual boreholes is an estimate. The termination depth of all boreholes will be at the discretion of the Department s Representative. Drilling of all boreholes shall be with non-percussion or percussion rotary drills at locations shown on the Project Drawing or as designated by the Department s Representative. This does not preclude the use of churn drills for installing and handling casing pipe or reopening boreholes, if required. The Department s Representative will designate the location and order of drilling of the holes. The Contractor shall be responsible for determining the location of all underground and overhead utilities such as, but not limited to telephone, cable, sewer, gas, water and electric. Should the location of any utility prohibit the drilling of any borehole, the Contractor shall advise the Department s Representative for possible relocation of said borehole. The Contractor shall not be paid for any borehole or part of any borehole that should puncture a utility. The rotary drills shall be equipped with complete dust control systems or mechanisms to collect dust produced in the process of drilling and prevent the discharge of dust into the atmosphere. The dust control systems shall be of ample capacity to serve under all 5

6 conditions. Drilling rigs shall be of sufficient size and capacity to carry on drilling operations in an efficient manner. All precautions shall be taken by the Contractor to ensure that the hole is plumb when drilling boreholes. A stabilizer, not less than ten feet (10 ) in length and one-inch (1 ) less in diameter than the diameter of the bit, shall be attached to the cutting bit and stem. The Contractor shall be required to drill boreholes, sufficient in diameter to accommodate the specified overburden-casing pipe from the surface through the unconsolidated material (wash) to a point five feet (5 ) into the solid rock strata. After the overburden casing pipe has been properly set and sealed with cement grout, the Contractor shall then continue drilling. Drilling shall proceed through the rock strata with a drill bit sufficient in diameter to accommodate the specified borehole casing pipe to the requested target depth. The Contractor shall be required to drill boreholes through the rock strata with a drill bit sufficient in diameter to accommodate the specified borehole casing pipe to the requested target depth. When an opening in a coal bed or other void is encountered, the Contractor shall probe the opening or void to determine its depth and condition. Payment for such probing will be as drilling at the specified diameter and at the same price per linear foot listed in the Contract Unit Price. The Contractor shall keep and furnish to the Department s Representative an accurate log of the completed boreholes, which shall include, but is not limited to, the type and condition of the unconsolidated overburden (wash), rock strata and coal beds. A more detailed description of the information required for each borehole log is outlined in Contract Item, Mobilization and Demobilization, Section 1.3 Delivery of Records. In the event the walls of the boreholes begin to cave or barrel, the Contractor shall be required to either introduce sodium bentonite into the borehole or to attempt any other method the Contractor deems suitable to stabilize the borehole wall, providing it meets with the approval of the Department s Representative. Any borehole that may be lost or become unusable must be reopened or replaced at the expense of the Contractor. Any borehole that is lost or becomes unusable must be sealed according to the Technical Specifications at the Contractor's expense. If additional boreholes are necessary, in the opinion of the Department s Representative, the Contractor shall drill same at the price per linear foot listed in the Contract for similar size boreholes. 6

7 4.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, for non-percussion or percussion rotary drilling of the diameter specified will be made on the basis of the linear feet of holes actually drilled and accepted by the Department s Representative, but only to the extent directed. Payment will be made at the Contract Unit Price bid per Linear Foot for Contract Items, A) Drilling Borehole To Accommodate Eight-Inch (8 ) I.D Surface Casing Pipe and B) Drilling Borehole to Accommodate Four-Inch (4 ) I.D. Casing Pipe which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. 5. FURNISHING AND INSTALLING PVC AND STEEL CASING PIPE INCLUDING GROUTING 5.1 SCOPE The work covered by this section consists of providing all labor, material, equipment and incidentals required to furnish and install eight-inch (8 ) and four-inch (4 ) I.D. casing pipe into the boreholes. 5.2 PROCEDURE Eight-inch (8 ) inside diameter overburden steel casing pipe, as specified, shall be installed in the boreholes from the surface through the unconsolidated overburden (wash) to a point five feet (5 ) into solid rock strata. The casing pipe shall then be set and sealed tightly with cement grout before continuing the drilling of the boreholes through the rock strata unless otherwise directed by the Department s Representative. For each well, the final stickup of the steel casing shall be a minimum of eighteen inches (18 ), unless otherwise specified. A locking cap shall be furnished and installed on the steel casing. The Contractor shall furnish and install new plastic pipe in all boreholes, which shall be used for monitoring purposes. Plastic casing pipe shall be Schedule 40 with belled endjoint couplings. Each joint shall be primed and glued using appropriate PVC primer and cement. Each joint shall also be secured using four (4) stainless steel screws. The screws shall be long enough to penetrate the inner pipe as much as possible but not through the inner pipe. The pipe shall rest on the bottom of the borehole and the bottom five-feet (5 ) of pipe shall have three (3) rows of one inch (1 ) diameter holes spaced a maximum of six inches (6 ) apart. The top of the four-inch (4 ) plastic casing shall not be more than ten-inches (10 ) lower than the top of the steel outer casing. The Department s Representative shall specify casing pipe size and type and shall approve all casing pipe before it is installed in the boreholes. 7

8 The plastic pipe shall be grouted in place to the ground surface using the following procedure. A metal grout basket shall be installed on the casing at a depth of approximately ten-feet (10 ) above the roof of the mine (top of the mine void). A rubber fernco will not be accepted as a grout basket. Approximately five-feet (5 ) of time release bentonite pellets shall be added on top of the grout basket. Prior to grouting, the pellets shall be given enough time to activate according to the manufacturers specifications. Grout shall be placed using tremie pipe. Depending upon the depth of the hole, grouting may be required to be completed in stages as directed by the Department s Representative. Refer to Figure No. 1 and Figure No. 2 for typical above ground and flush mount well construction diagrams. 5.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, for casing pipe will be made on the basis of the linear feet of casing pipe of the diameter and type specified, furnished and installed, but only to the extent directed. Payment will be made at the Contract Unit Price bid per linear foot for Contract Items, Furnishing and Installing Plastic and Steel Casing Pipe, A) Eight-Inch (8 ) I.D. Overburden Casing Steel Pipe Including Grouting, and B) Four-Inch (4 ) I.D. Casing Plastic Pipe Including Grouting, Plug and Cap, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. 6. BOREHOLE ABANDONMENT 6.1 SCOPE The work covered by this section consists of furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily seal unsuitable boreholes as defined under this work item. 6.2 PROCEDURE If a borehole is considered unsuitable for future monitoring use as determined by the Department s Representative, the Contractor shall be required to seal each borehole in the following manner: 1. For boreholes not reaching the target elevation and terminating in solid bedrock, cement grout, placed using tremie pipe, shall be placed into the borehole to within one foot (1 ) of the surface. A plug of the contractor s choice may be required at the direction of the Department s Representative. 8

9 2. For boreholes reaching the target elevation and encountering a coal pillar or conditions deemed unsuitable for monitoring as determined by the Department s Representative, the Contractor inserts a plug of his choice, which is acceptable to the Department s Representative, in the borehole approximately ten-feet (10 ) above the bedrock-coal interface or to a point selected by the Department s Representative (see Figure No. 3). A minimum of five feet (5 ) of time release bentonite pellets shall be added on top of the plug. Prior to grouting, the pellets shall be given enough time to activate according to the manufacturers specifications. At the direction of the Department s Representative, the borehole shall be filled with cement grout using tremie pipe to within one foot (1 ) of the surface. Depending upon the depth of the hole, grouting may be required to be completed in stages as directed by the Department s Representative. 3. The surface will be restored to as good as or better than original condition. Except with the permission of the Department s Representative, the Contractor shall not abandon nor complete any borehole, or remove any casing or drilling equipment, without first affording the Department s Representative the opportunity to obtain the position and the depth of the borehole prior to abandonment or completion and any other information which the Department s Representative may require. No payment will be made for any borehole which has been abandoned by the Contractor before reaching the depth, elevation or condition specified, and no payment will be made for the sealing of the borehole in accordance with the specifications, unless the Department s Representative approved and accepts the borehole as being completed. The Department s Representative may, at his option, accept a borehole which fails to reach the required depth due to unusual subsurface conditions which, in his opinion, could not reasonably have been anticipated. 6.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved for sealing boreholes, will be made on the basis of each borehole abandoned, but only to the extent directed and accepted by the Department s Representative. Payment will be made at the Contract Unit Price bid per borehole for Contract Item, Borehole Abandonment, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. 7. RESTORATION 7.1 SCOPE The work covered under this section consists of providing all labor, material, equipment and other incidentals necessary to restore the area surrounding a borehole and the access to a borehole to a condition equal to or better than that which existed prior to the start of 9

10 work. The work included in this section is considered discretionary and must be directed, approved and accepted by the Department s Representative since clean-up and restoration is considered incidental to and included in Contract Item, Mobilization and Demobilization. 7.2 PROCEDURE In the case of drill holes located on private property, restoration includes, but is not limited to, repairing or replacing any sidewalks, fences, lawns, seeding and access road, and other improvements to the property which may have been damaged or removed as a result of the work, but only to the extent directed, approved and accepted by the Department s Representative. 7.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, for restoration at the specified locations will be made on the basis of each borehole restored, but only to the extent directed, approved and accepted by the Department s Representative. Payment will be made at the Contract Unit Price bid per each borehole for Contract Item, Restoration, which price and payment shall constitute full compensation for furnishing all labor, material, equipment, supplies and all necessary incidentals required to satisfactorily complete this item of work. No payment will be made for restoration that has not been directed, approved and accepted by the Department s Representative since clean-up and restoration is considered incidental to and included in Contract Item, Mobilization and Demobilization. 8. STAND-BY TIME 8.1 SCOPE The work item covered by this section is intended to address any delays in drilling in which a drill rig and crew is ordered by the Department s Representative to stand idle. 8.2 PROCEDURE When the Contractor is ordered by the Department s Representative to delay the drilling of any borehole, the Contractor will be reimbursed for any such delays providing that the delays are the sole responsibility of the Department s Representative and the delays are in excess of one-half (1/2) hour in duration. Stand-by time shall not be used for payment to the Contractor for delays caused by equipment breakdown and malfunctions or for delays caused by non-availability of necessary equipment and supplies. Such delays shall be considered the sole responsibility of the Contractor and shall be incidental to other items of work and no 10

11 additional compensation will be allowed. No payment for stand-by time will be made for items of equipment other than a complete drill rig and crew in full operating condition. A crew shall consist of a driller and helper and if any delay does occur, the Department s Representative will record it on a daily basis with dates and times directed to be idle. 8.3 MEASUREMENT AND PAYMENT Measurement, when accepted and approved, will be made on the basis of hours a drilling rig and crew is ordered by the Department s Representative to stand idle, but only to the extent directed by the Department s Representative. Payment will be made at the Contract Unit Price bid per hour for Stand-by Time and will be divided no finer than by one-half (1/2) hour increments, which price and payment shall constitute full compensation for the delay of a drill rig and crew. 9. INSPECTIONS Ample opportunity shall be furnished at all times to the Department s Representative for inspecting the work. If any imperfect work is performed at any time, the defects therein shall be remedied by the Contractor, at his expense, to the full satisfaction of the Department s Representative. No drilling or field-testing shall be done except in the presence of the inspector or Department s Representative, unless specific permission has been granted to the contrary. The presence of an inspector, or the keeping of separate drilling records by the Department s Representative, shall not relieve the Contractor of the responsibility for work specified in the Contract. 11